Institute of Fundamental Technological Research
Polish Academy of Sciences

Staff

Dorota Kołbuk-Konieczny, PhD, DSc

Laboratory of Polymers and Biomaterials (SPPiB)
position: Assistant Professor
telephone: (+48) 22 826 12 81 ext.: 425
room: 338
e-mail:
ORCID: 0000-0001-9651-7087

Doctoral thesis
2013-02-28 Wpływ warunków elektroprzędzenia na strukturę i właściwości jedno-i dwuskładnikowych nanowłókien polimerowych stosowanych w inżynierii tkankowej 
supervisor -- Paweł Sajkiewicz, PhD, DSc, IPPT PAN
 
Habilitation thesis
2024-10-24 Biomimetyczne i biodegradowalne rusztowania komórkowe – od struktury do funkcjonalności 
Supervision of doctoral theses
1.  2019-05-30
co-supervisor
Urbanek-Świderska Olga   Wpływ biegunowości napięcia w procesie elektroprzędzenia na wybrane właściwości i modyfikację powierzchni nanowłókien oraz odpowiedź komórkową 

Recent publications
1.  Zaszczyńska A., Gradys A. D., Kołbuk-Konieczny D., Zabielski K., Szewczyk P., Stachewicz U., Sajkiewicz P. Ł., Poly(L-lactide)/nano-hydroxyapatite piezoelectric scaffolds for tissue engineering, Micron, ISSN: 0968-4328, DOI: 10.1016/j.micron.2024.103743, Vol.188, pp.103743-1-15, 2025

Abstract:
The development of bone tissue engineering, a field with significant potential, requires a biomaterial with high bioactivity. The aim of this manuscript was to fabricate a nanofibrous poly(L-lactide) (PLLA) scaffold containing nano-hydroxyapatite (nHA) to investigate PLLA/nHA composites, particularly the effect of fiber arrangement and the addition of nHA on the piezoelectric phases and piezoelectricity of PLLA samples. In this study, we evaluated the effect of nHA particles on a PLLA-based electrospun scaffold with random and aligned fiber orientations. The addition of nHA increased the surface free energy of PLLA/nHA (42.9 mN/m) compared to PLLA (33.1 mN/m) in the case of aligned fibers. WAXS results indicated that at room temperature, all the fibers are in an amorphous state indicated by a lack of diffraction peaks and amorphous halo. DSC analysis showed that all samples located in the amorphous/disordered alpha' phase crystallize intensively at temperatures just above the Tg and recrystallize on further heating, achieving significantly higher crystallinity for pure PLLA than for doped nHA, 70 % vs 40 %, respectively. Additionally, PLLA/nHA fibers show a lower heat capacity for PLLA in the amorphous state, indicating that nHA reduces the molecular mobility of PLLA. Moreover, piezoelectric constant d33 was found to increase with the addition of nHA and for the aligned orientation of the fibers. In vitro tests confirmed that the addition of nHA and the aligned orientation of nanofibers increased osteoblast proliferation.

Keywords:
Scaffolds, Tissue engineering, Bone tissue engineering, Smart medicine, Biodegradable polymers, Regenerative medicine

Affiliations:
Zaszczyńska A. - IPPT PAN
Gradys A. D. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Zabielski K. - IPPT PAN
Szewczyk P. - other affiliation
Stachewicz U. - AGH University of Science and Technology (PL)
Sajkiewicz P. Ł. - IPPT PAN
2.  Moczulska-Heljak M., Heljak M., Sajkiewicz P. Ł., Kołbuk-Konieczny D., Unraveling hierarchically ordered melt electro-written tissue engineering scaffolds: Morphological and mechanical insights, POLYMER, ISSN: 0032-3861, DOI: 10.1016/j.polymer.2024.127717, Vol.313, pp.127717-1-9, 2024

Abstract:
Addressing critical tissue defects treatment remains a pressing challenge in medicine and bioengineering. Tissue engineering (TE) scaffolds, characterized by porous architectures suitable to cell growth, is a pivotal solution. Recent advances in additive techniques have revolutionized scaffold fabrication, enabling precise control over complex porous structures. This study conducts a comprehensive analysis of hierarchically ordered melt electrospun written (MEW) TE scaffolds, elucidating the relationships between fabrication parameters and their morphological and mechanical properties. Leveraging the phenomenon of melt jet deposit buckling, characteristic hierarchically ordered porous architectures were attained. The study explores the fabrication potential of hierarchically ordered porous MEW architectures across varied voltages, feed rates, and needle sizes. Morphometric parameters, including percent porosity, density of fiber intersections, and fiber diameter, were identified. It was revealed that for feed rates exceeding 20 mm/s, resultant fiber diameters were unaffected by voltage. However, increasing voltage leads to noticeable reduction of mesh stiffness due to the coiled fibers presence. Exceptions occur at the feed rate of 20 mm/s and for needle G24, where stiffness surpasses those of regular primary pattern, which could be attributed to increased number of fiber interconnections.

Keywords:
MEW, Hierarchically ordered meshes, Coiled architectures, Entangled meshes

Affiliations:
Moczulska-Heljak M. - IPPT PAN
Heljak M. - Warsaw University of Technology (PL)
Sajkiewicz P. Ł. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
3.  Zaszczyńska A., Kołbuk-Konieczny D., Gradys A. D., Sajkiewicz P. Ł., Development of Poly(methyl methacrylate)/nano-hydroxyapatite (PMMA/nHA) Nanofibers for Tissue Engineering Regeneration Using an Electrospinning Technique, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym16040531, Vol.16, No.4, pp.531-1-19, 2024

Abstract:
The study explores the in vitro biocompatibility and osteoconductivity of poly(methyl methacrylate)/nano-hydroxyapatite (PMMA/nHA) composite nanofibrous scaffolds for bone tissue engineering (BTE). Electrospun scaffolds, exhibiting both low and high fiber orientation, were investigated. The inclusion of hydroxyapatite nanoparticles enhances the osteoconductivity of the scaffolds while maintaining the ease of fabrication through electrospinning. SEM analysis confirms the high-quality morphology of the scaffolds, with successful incorporation of nHA evidenced by SEM-EDS and FTIR methods. DSC analysis indicates that nHA addition increases the PMMA glass transition temperature (Tg) and reduces stress relaxation during electrospinning. Furthermore, higher fiber orientation affects PMMA Tg and stress relaxation differently. Biological studies demonstrate the composite material’s non-toxicity, excellent osteoblast viability, attachment, spreading, and proliferation. Overall, PMMA/nHA composite scaffolds show promise for BTE applications.

Keywords:
biomaterials, nanofibrous scaffolds, bone tissue engineering

Affiliations:
Zaszczyńska A. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Gradys A. D. - IPPT PAN
Sajkiewicz P. Ł. - IPPT PAN
4.  Altangerel A., Cegielska O., Kołbuk D., Kalaska B., Sajkiewicz P.Ł., On-Demand Sequential Release of Dual Drug from pH-Responsive Electrospun Janus Nanofiber Membranes toward Wound Healing and Infection Control, ACS Applied Materials and Interfaces, ISSN: 1944-8244, DOI: 10.1021/acsami.3c13676, Vol.16, No.1, pp.153-165, 2023

Abstract:
Drugs against bacteria and abnormal cells, such as antibiotics and anticancer drugs, may save human lives. However, drug resistance is becoming more common in the clinical world. Nowadays, a synergistic action of multiple bioactive compounds and their combination with smart nanoplatforms has been considered an alternative therapeutic strategy to fight drug resistance in multidrug-resistant cancers and microorganisms. The present study reports a one-step fabrication of innovative pH-responsive Janus nanofibers loaded with two active compounds, each in separate polymer compartments for synergistic combination therapy. By dissolving one of the compartments from the nanofibers, we could clearly demonstrate a highly yielded anisotropic Janus structure with two faces by scanning electron microscopy (SEM) analysis. To better understand the distinctive attributes of Janus nanofibers, several analytical methods, such as X-ray diffraction (XRD), FTIR spectroscopy, and contact angle goniometry, were utilized to examine and compare them to those of monolithic nanofibers. Furthermore, a drug release test was conducted in pH 7.4 and 6.0 media since the properties of Janus nanofibers correlate significantly with different environmental pH levels. This resulted in the on-demand sequential codelivery of octenidine (OCT) and curcumin (CUR) to the corresponding pH stimulus. Accordingly, the antibacterial properties of Janus fibers against Escherichia coli and Staphylococcus aureus, tested in a suspension test, were pH-dependent, i.e., greater in pH 6 due to the synergistic action of two active compounds, and Eudragit E100 (EE), and highly satisfactory. The biocompatibility of the Janus fibers was confirmed in selected tests.

Keywords:
Janus nanofiber, on-demand release, dual-drug, antibacterial activity, side-by-side electrospinning

Affiliations:
Altangerel A. - IPPT PAN
Cegielska O. - IPPT PAN
Kołbuk D. - IPPT PAN
Kalaska B. - other affiliation
Sajkiewicz P.Ł. - IPPT PAN
5.  Gloc M., Przybysz S., Dulnik J., Kołbuk-Konieczny D., Wachowski M., Kosturek R., Ślęzak T., Krawczyńska A., Ciupiński , A Comprehensive Study of a Novel Explosively Hardened Pure Titanium Alloy for Medical Applications, Materials, ISSN: 1996-1944, DOI: 10.3390/ma16227188, Vol.16, No.22, pp.7188--1-19, 2023

Abstract:
Pure titanium is gaining increasing interest due to its potential use in dental and orthopedic applications. Due to its relatively weak mechanical parameters, a limited number of components manufactured from pure titanium are available on the market. In order to improve the mechanical parameters of pure titanium, manufacturers use alloys containing cytotoxic vanadium and aluminum. This paper presents unique explosive hardening technology that can be used to strengthen pure titanium parameters. The analysis confirms that explosive induced α-ω martensitic transformation and crystallographic anisotropy occurred due to the explosive pressure. The mechanical properties related to residual stresses are very nonuniform. The corrosion properties of the explosive hardened pure titanium test do not change significantly compared to nonhardened titanium. The biocompatibility of all the analyzed samples was confirmed in several tests. The morphology of bone cells does not depend on the titanium surface phase composition and crystallographic orientation.

Keywords:
explosive hardening, pure titanium, bioimplants, titanium alloys

Affiliations:
Gloc M. - Warsaw University of Technology (PL)
Przybysz S. - Institute of High Pressure Physics, Polish Academy of Sciences (PL)
Dulnik J. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Wachowski M. - other affiliation
Kosturek R. - other affiliation
Ślęzak T. - other affiliation
Krawczyńska A. - Warsaw University of Technology (PL)
Ciupiński  - Warsaw University of Technology (PL)
6.  Altangerel A., Moazzami Goudarzi Z., Cegielska O., Gradys A.D., Kołbuk-Konieczny D., Kalaska B., Ruszczyńska A., Sajkiewicz P.Ł., A facile one-stone-two-birds strategy for fabricating multifunctional 3D nanofibrous scaffolds, Biomaterials Science, ISSN: 2047-4849, DOI: 10.1039/D3BM00837A, Vol.11, No.16, pp.5502-5516, 2023

Abstract:
Local bacterial infections lead to delayed wound healing and in extreme cases, such as diabetic foot ulcers, to non-healing due to the impaired cellular function in such wounds. Thus, many scientists have focused on developing advanced therapeutic platforms to treat infections and promote cellular proliferation and angiogenesis. This study presents a facile approach for designing nanofibrous scaffolds in three dimensions (3D) with enhanced antibacterial activity to meet the need of treating chronic diabetic wounds. Being a cationic surfactant as well as an antimicrobial agent, octenidine (OCT) makes a 2D membrane hydrophilic, enabling it to be modified into a 3D scaffold in a “one stone, two birds” manner. Aqueous sodium borohydride (NaBH4) solution plays a dual role in the fabrication process, functioning as both a reducing agent for the in situ synthesis of silver nanoparticles (Ag NPs) anchored on the nanofiber surface and a hydrogen gas producer for expanding the 2D membranes into fully formed 3D nanofiber scaffolds, as demonstrated by morphological analyses. Various techniques were used to characterize the developed scaffold (e.g., SEM, XRD, DSC, FTIR, and surface wettability), demonstrating a multilayered porous structure and superhydrophilic properties besides showing sustained and prolonged release of OCT (61% ± 1.97 in 144 h). Thanks to the synergistic effect of OCT and Ag NPs, the antibacterial performance of the 3D scaffold was significantly higher than that of the 2D membrane. Moreover, cell viability was studied in vitro on mouse fibroblasts L929, and the noncytotoxic character of the 3D scaffold was confirmed. Overall, it is shown that the obtained multifunctional 3D scaffold is an excellent candidate for diabetic wound healing and skin repair.

Affiliations:
Altangerel A. - IPPT PAN
Moazzami Goudarzi Z. - IPPT PAN
Cegielska O. - IPPT PAN
Gradys A.D. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Kalaska B. - other affiliation
Ruszczyńska A. - other affiliation
Sajkiewicz P.Ł. - IPPT PAN
7.  Silva M.J., Dias Y.J., Zaszczyńska A., Kołbuk-Konieczny D., Kowalczyk T., Sajkiewicz P. Ł., Yarin A., Three-phase bio-nanocomposite natural-rubber-based microfibers reinforced with cellulose nanowhiskers and 45S5 bioglass obtained by solution blow spinning, JOURNAL OF APPLIED POLYMER SCIENCE, ISSN: 0021-8995, DOI: 10.1002/app.54661, Vol.140, No.45, pp.e54661-1-18, 2023

Abstract:
Aiming at biomedical applications, the present work developed a new bio-nanocomposite fibrous mat based on natural rubber (NR) reinforced with 45S5 bioglass particles (BG) and cellulose nanowhiskers (CNW), which reveals excellent mechanical properties, good biocompatibility and bioactivity properties. Analyses of the specimens were conducted by means of morphological observa-tions (SEM) and thermal analysis (TG/DTG), as well as mechanical tests used to verify the effect of the incorporation of BG particles and CNW on the ultimate properties of these flexible NR-CWN/BG fibrous membranes. An SEM analysis revealed that all filaments possessed a ribbon-like morphology, with increasing diameters as the BG concentration increased. This likely results from an increased viscosity of the solution used for fiber blowing. In comparison with neat NR fibrous mats, the ultimate mechanical properties of bio-nanocomposites were sig-nificantly improved due to the presence of CNW and BG particles dispersed in the NR matrix. According to the TG/DTG analysis, the specimens' thermal stability was unaffected by the high BG content, and the thermal profiles were similar, with isoprene chains decomposition of the NR occurring between 350 and 450°C. In-vitro analysis on fibroblasts confirmed that the bio-nanocomposite fibrous mats are noncytotoxic. It was found that fibrous mats enhanced cellular growth and hold great promise for tissue engineering applications.

Keywords:
bioactive particles,cellulose nanowhiskers,fibrous mat bio-nanocomposite,natural rubber

Affiliations:
Silva M.J. - other affiliation
Dias Y.J. - other affiliation
Zaszczyńska A. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Kowalczyk T. - IPPT PAN
Sajkiewicz P. Ł. - IPPT PAN
Yarin A. - Technion-Israel Institute of Technology (IL)
8.  Kołakowska A., Kołbuk-Konieczny D., Chwojnowski A., Rafalski A., Gadomska-Gajadhur A., Chitosan-Based High-Intensity Modification of the Biodegradable Substitutes for Cancellous Bone, Journal of Functional Biomaterials, ISSN: 2079-4983, DOI: 10.3390/jfb14080410, Vol.14, No.8, pp.410-1-15, 2023

Abstract:
An innovative approach to treating bone defects is using synthetic bone substitutes made of biomaterials. The proposed method to obtain polylactide scaffolds using the phase inversion technique with a freeze extraction variant enables the production of substitutes with morphology similar to cancellous bone (pore size 100–400 µm, open porosity 94%). The high absorbability of the implants will enable their use as platelet-rich plasma (PRP) carriers in future medical devices. Surface modification by dipping enabled the deposition of the hydrophilic chitosan (CS) layer, maintaining good bone tissue properties and high absorbability (850% dry weight). Introducing CS increases surface roughness and causes local changes in surface free energy, promoting bone cell adhesion. Through this research, we have developed a new and original method of low-temperature modification of PLA substitutes with chitosan. This method uses non-toxic reagents that do not cause changes in the structure of the PLA matrix. The obtained bone substitutes are characterised by exceptionally high hydrophilicity and morphology similar to spongy bone. In vitro studies were performed to analyse the effect of morphology and chitosan on cellular viability. Substitutes with properties similar to those of cancellous bone and which promote bone cell growth were obtained.

Keywords:
chitosan, polylactide, bone substitute, tissue regeneration

Affiliations:
Kołakowska A. - other affiliation
Kołbuk-Konieczny D. - IPPT PAN
Chwojnowski A. - Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences (PL)
Rafalski A. - other affiliation
Gadomska-Gajadhur A. - Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences (PL)
9.  Niemczyk-Soczyńska B., Kołbuk-Konieczny D., Mikułowski G., Ciechomska I.A., Sajkiewicz P.Ł., Methylcellulose/agarose hydrogel loaded with short electrospun PLLA/laminin fibers as an injectable scaffold for tissue engineering/3D cell culture model for tumour therapies, RSC Advances, ISSN: 2046-2069, DOI: 10.1039/D3RA00851G, Vol.13, No.18, pp.11889-11902, 2023

Abstract:
This research aimed at designing and fabricating a smart thermosensitive injectable methylcellulose/agarose hydrogel system loaded with short electrospun bioactive PLLA/laminin fibers as a scaffold for tissue engineering applications or 3D cell culture models. Considering ECM-mimicking morphology and chemical composition, such a scaffold is capable of ensuring a hospitable environment for cell adhesion, proliferation, and differentiation. Its viscoelastic properties are beneficial from the practical perspective of minimally invasive materials that are introduced to the body via injection. Viscosity studies showed the shear-thinning character of MC/AGR hydrogels enabling the potential injection ability of highly viscous materials. Injectability tests showed that by tuning the injection rate, even a high amount of short fibers loaded inside of hydrogel could be efficiently injected into the tissue. Biological studies showed the non-toxic character of composite material with excellent viability, attachment, spreading, and proliferation of fibroblasts and glioma cells. These findings indicate that MC/AGR hydrogel loaded with short PLLA/laminin fibers is a promising biomaterial for both tissue engineering applications and 3D tumor culture models.

Affiliations:
Niemczyk-Soczyńska B. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Mikułowski G. - IPPT PAN
Ciechomska I.A. - Nencki Institute of Experimental Biology, Polish Academy of Sciences (PL)
Sajkiewicz P.Ł. - IPPT PAN
10.  Urbanek-Świderska O., Moczulska-Heljak M., Wróbel M., Mioduszewski A., Kołbuk-Konieczny D., Advanced Graft Development Approaches for ACL Reconstruction or Regeneration, Biomedicines, ISSN: 2227-9059, DOI: 10.3390/biomedicines11020507, Vol.11, No.2, pp.507-1-26, 2023

Abstract:
The Anterior Cruciate Ligament (ACL) is one of the major knee ligaments, one which is greatly exposed to injuries. According to the British National Health Society, ACL tears represent around 40% of all knee injuries. The number of ACL injuries has increased rapidly over the past ten years, especially in people from 26–30 years of age. We present a brief background in currently used ACL treatment strategies with a description of surgical reconstruction techniques. According to the well-established method, the PubMed database was then analyzed to scaffold preparation methods and materials. The number of publications and clinical trials over the last almost 30 years were analyzed to determine trends in ACL graft development. Finally, we described selected ACL scaffold development publications of engineering, medical, and business interest. The systematic PubMed database analysis indicated a high interest in collagen for the purpose of ACL graft development, an increased interest in hybrid grafts, a numerical balance in the development of biodegradable and nonbiodegradable grafts, and a low number of clinical trials. The investigation of selected publications indicated that only a few suggest a real possibility of creating healthy tissue. At the same time, many of them focus on specific details and fundamental science. Grafts exhibit a wide range of mechanical properties, mostly because of polymer types and graft morphology. Moreover, most of the research ends at the in vitro stage, using non-certificated polymers, thus requiring a long time before the medical device can be placed on the market. In addition to scientific concerns, official regulations limit the immediate introduction of artificial grafts onto the market.

Keywords:
ligament,biomaterial,tissue engineering,regeneration,implant,scaffold,synthetic polymer,natural polymer

Affiliations:
Urbanek-Świderska O. - IPPT PAN
Moczulska-Heljak M. - IPPT PAN
Wróbel M. - Fraunhofer Institute for Cell Therapy and Immunology IZI (DE)
Mioduszewski A. - other affiliation
Kołbuk-Konieczny D. - IPPT PAN
11.  Silva M.J., Dias Y.J., Zaszczyńska A., Rojas Robles J., Abiade J., Kowalczyk T., Kołbuk-Konieczny D., Sajkiewicz P., Yarin A.L., Biocomposite-based fibrous scaffolds of natural rubber/polyhydroxybutyrate blend reinforced with 45S5 bioglass aiming at biomedical applications, Polymer Composites, ISSN: 0272-8397, DOI: 10.1002/pc.27839, pp.1-21, 2023

Abstract:
The solution blow spinning technique was used to fabricate a new biocomposite fibrous mat consisting of natural rubber (NR) and polyhydroxybutyrate (PHB) bioblend, with various loads of 45S5 bioglass (BG) particles. According to SEM analysis, NR fibers exhibited ribbon-like morphologies, whereas the addition of PHB resulted in improved fiber formation and a reduction in their diameter. In NR-PHB/BG biocomposites with varying BG loadings, typical thermal degradation events of PHB (stage i) and NR (stage ii) were observed. In comparison with pure PHB, the TG/DTG curves of NR-PHB/BG specimens revealed a lower stage i degradation peak. Such an outcome is possibly due to the fact that PHB in the NR-PHB fibers is located predominantly at the surface, that is, PHB is more susceptible to thermal degradation. The NR-PHB/BG biocomposite possessed an increased stiffness due to the addition of PHB and BG, resulting in an increased stress and a decreased strain at rupture compared to the pure NR and NR-PHB mats. DMA analysis revealed two well-defined regions, above and below the glass transition temperature (Tg), for the storage modulus (E') of the NR-PHB/BG specimens. The values of E' were in both regions for NR-PHB/BG specimens increased at higher BG content. The measured tanδ = E″/E' was used to determine the Tg value for all specimens, with Tg found to be in the −49 to −46°C range. Finally, NR-PHB/BG biocomposite fibrous were proven noncytotoxic by in-vitro testing on fibroblasts. These biocomposites enhanced cell growth, holding great promise for tissue engineering applications.

Keywords:
45S5 bioglass, biocomposite fibrous mat, biomedical applications, natural rubber, polyhydroxybutyrate, solution blow spinning

Affiliations:
Silva M.J. - other affiliation
Dias Y.J. - other affiliation
Zaszczyńska A. - IPPT PAN
Rojas Robles J. - other affiliation
Abiade J. - other affiliation
Kowalczyk T. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Yarin A.L. - Technion-Israel Institute of Technology (IL)
12.  Tabakoğlu S., Kołbuk-Konieczny D., Sajkiewicz P., Multifluid electrospinning for multi-drug delivery systems: pros and cons, challenges, and future directions, Biomaterials Science, ISSN: 2047-4849, DOI: 10.1039/D2BM01513G, pp.1-25, 2022

Abstract:
The electrospinning method has been widely used to produce nano/micro fibers for various applications. As a drug delivery system, electrospun fibers display many advantages such as controlled drug delivery kinetics and the ability to deliver drugs locally. A drug delivery system improves delivery efficiency and reduces possible toxic effects. In particular, multiaxial fibers consisting of two or more fluid components have drawn attention for the simultaneous administration of multiple therapeutic agents for sustained delivery and effective treatment. This review discusses recently studied multi-compartment electrospun fibers, including side-by-side (Janus) and axially symmetric fibers – coaxial and triaxial – from the perspective of multi-drug incorporation. It begins with an overview of conventional uniaxial single-fluid electrospinning methods for drug delivery applications, then highlights the advantages of multi-compartment fibers for multi-substance loading/delivery and the advances in triaxial fibers that seem to be promising from the perspective of challenges for dressings and tissue regeneration. Furthermore, drug release mechanisms and kinetics are discussed in the controlled delivery of multiple therapeutics in fibers. In the conclusion, current biomedical applications of multi-drug delivery systems in selected applications and future perspectives are presented.

Affiliations:
Tabakoğlu S. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
13.  Czwartos J., Zaszczyńska A., Nowak-Stępniowska A., Fok T., Budner B., Bartnik A., Wachulak P., Kołbuk D., Sajkiewicz P., Fiedorowicz H., The novel approach to physico-chemical modification and cytocompatibility enhancement of fibrous polycaprolactone (PCL) scaffolds using soft X-ray/extreme ultraviolet (SXR/EUV) radiation and low-temperature, SXR/EUV induced, nitrogen and oxygen plasmas, APPLIED SURFACE SCIENCE, ISSN: 0169-4332, DOI: 10.1016/j.apsusc.2022.154779, Vol.606, pp.154779-1-12, 2022

Abstract:
The fundamental aspect of the fabrication of microporous, fibrous biomaterials in form of scaffolds is the optimization of their surface properties to enhance cellular response. In this work, a novel approach to physico-chemical modification and bioactivity enhancement of electrospun fibrous polycaprolactone (PCL) nonwovens using soft X-ray/extreme ultraviolet (SXR/EUV) irradiation and exposure to a low-temperature, SXR/EUV induced, nitrogen and oxygen plasmas is presented for the first time. Chemical alterations and morphology of the fibrous structure of irradiated PCL mats were examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The impact of introduced changes on viability, morphology, and adhesion of L929 mouse fibroblasts was examined. It was found that simultaneous interaction of SXR/EUV radiation and N2 or O2 photoionized plasmas led to strong chemical decomposition of the surface of fibrous PCL mats. Also, mats’ spatial porous structure was not damaged and the fibers were not broken or fused. All modified samples demonstrated cyto-compatible and non-cytotoxic properties. Enhancement of L929 cell adhesion and increased proliferation were also observed.

Keywords:
Soft X-ray/extreme ultraviolet (SXR/EUV) radiation, Low-temperature plasma treatment, Electrospun polycaprolactone (PCL) nonwovens, XPS analysis, L929 mouse fibroblasts, Cytocompatibility enhancement

Affiliations:
Czwartos J. - other affiliation
Zaszczyńska A. - IPPT PAN
Nowak-Stępniowska A. - other affiliation
Fok T. - other affiliation
Budner B. - other affiliation
Bartnik A. - other affiliation
Wachulak P. - other affiliation
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Fiedorowicz H. - other affiliation
14.  Jeznach O., Kołbuk D., Reich T., Sajkiewicz P., Immobilization of Gelatin on Fibers for Tissue Engineering Applications: A Comparative Study of Three Aliphatic Polyesters, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym14194154, Vol.14, No.19, pp.4154-1-21, 2022

Abstract:
Immobilization of cell adhesive proteins on the scaffold surface has become a widely reported method that can improve the interaction between scaffold and cells. In this study, three nanofibrous scaffolds obtained by electrospinning of poly(caprolactone) (PCL), poly(L-lactide-co-caprolactone) (PLCL) 70:30, or poly(L-lactide) (PLLA) were subjected to chemical immobilization of gelatin based on aminolysis and glutaraldehyde cross-linking, as well as physisorption of gelatin. Two sets of aminolysis conditions were applied to evaluate the impact of amine group content. Based on the results of the colorimetric bicinchoninic acid (BCA) assay, it was shown that the concentration of gelatin on the surface is higher for the chemical modification and increases with the concentration of free NH2 groups. XPS (X-ray photoelectron spectroscopy) analysis confirmed this outcome. On the basis of XPS results, the thickness of the gelatin layer was estimated to be less than 10 nm. Initially, hydrophobic scaffolds are completely wettable after coating with gelatin, and the time of waterdrop absorption was correlated with the surface concentration of gelatin. In the case of all physically and mildly chemically modified samples, the decrease in stress and strain at break was relatively low, contrary to strongly aminolyzed PLCL and PLLA samples. Incubation testing performed on the PCL samples showed that a chemically immobilized gelatin layer is more stable than a physisorbed one; however, even after 90 days, more than 60% of the initial gelatin concentration was still present on the surface of physically modified samples. Mouse fibroblast L929 cell culture on modified samples indicates a positive effect of both physical and chemical modification on cell morphology. In the case of PCL and PLCL, the best morphology, characterized by stretched filopodia, was observed after stronger chemical modification, while for PLLA, there was no significant difference between modified samples. Results of metabolic activity indicate the better effect of chemical immobilization than of physisorption of gelatin.

Keywords:
gelatin, aminolysis, surface modification, electrospinning

Affiliations:
Jeznach O. - IPPT PAN
Kołbuk D. - IPPT PAN
Reich T. - other affiliation
Sajkiewicz P. - IPPT PAN
15.  Niemczyk-Soczyńska B., Gradys A., Kołbuk D., Krzton-Maziopa A., Rogujski P., Stanaszek L., Lukomska B., Sajkiewicz P., A methylcellulose/agarose hydrogel as an innovative scaffold for tissue engineering, RSC Advances, ISSN: 2046-2069, DOI: 10.1039/D2RA04841H, Vol.12, No.41, pp.26882-26894, 2022

Abstract:
In situ crosslinked materials are the main interests of both scientific and industrial research. Methylcellulose (MC) aqueous solution is one of the representatives that belongs to this family of thermosensitive materials. At room temperature, MC is a liquid whereupon during temperature increase up to 37 °C, it crosslinks physically and turns into a hydrogel. This feature makes it unique, especially for tissue engineering applications. However, the crosslinking rate of MC alone is relatively slow considering tissue engineering expectations. According to these expectations, the crosslinking should take place slowly enough to allow for complete injection and fill the injury avoiding clogging in the needle, and simultanously, it should be sufficiently fast to prevent it from relocation from the lesion. One of the methods to overcome this problem is MC blending with another substance that increases the crosslinking rate of MC. In these studies, we used agarose (AGR). These studies aim to investigate the effect of different AGR amounts on MC crosslinking kinetics, and thermal, viscoelastic, and biological properties. Differential Scanning Calorimetry (DSC) and dynamic mechanical analysis (DMA) measurements proved that AGR addition accelerates the beginning of MC crosslinking. This phenomenon resulted from AGR's greater affinity to water, which is crucial in this particular crosslinking part. In vitro tests, carried out using the L929 fibroblast line and mesenchymal stem cells (MSCs), confirmed that most of the hydrogel samples were non-cytotoxic in contact with extracts and directly with cells. Not only does this type of thermosensitive hydrogel system provide excellent mechanical and biological cues but also its stimuli-responsive character provides more novel functionalities for designing innovative scaffold/cell delivery systems for tissue engineering applications.

Affiliations:
Niemczyk-Soczyńska B. - IPPT PAN
Gradys A. - IPPT PAN
Kołbuk D. - IPPT PAN
Krzton-Maziopa A. - Warsaw University of Technology (PL)
Rogujski P. - other affiliation
Stanaszek L. - other affiliation
Lukomska B. - other affiliation
Sajkiewicz P. - IPPT PAN
16.  Jeznach O., Kołbuk D., Marzec M., Bernasik A., Sajkiewicz P., Aminolysis as a surface functionalization method of aliphatic polyester nonwovens: impact on material properties and biological response, RSC Advances, ISSN: 2046-2069, DOI: 10.1039/D2RA00542E, Vol.12, No.18, pp.11303-11317, 2022

Abstract:
It is reported in the literature that introducing amino groups on the surface improves cellular behaviour due to enhanced wettability and the presence of the positive charge. In this work, electrospun fibers were subjected to aminolysis under various conditions to investigate the impact of reaction parameters on the concentration of free NH2 groups, change of fiber properties, and the response of L929 cells. Three types of electrospun nonwovens obtained from poly(caprolactone) (PCL), poly(L-lactide-co-caprolactone) (PLCL) 70 : 30 and poly(L-lactide) (PLLA) were investigated. For all polymers, the concentration of NH2 groups increased with the diamine concentration and time of reaction. However, it was observed that PCL fibers require much stronger conditions than PLCL and PLLA fibers to reach the same level of introduced amine groups. X-ray photoelectron spectroscopy results clearly demonstrate that an aminolysis reaction is not limited to the surface of the material. Gel permeation chromatography results support this conclusion indicating global molecular weight reduction. However, it is possible to reach a compromise between the concentration of introduced amine groups and the change of mechanical properties. For most of the investigated conditions, aminolysis did not significantly change the water contact angle. Despite this, the change of L929 and MG63 cell shape to being more spread confirmed the positive effect of the presence of the amine groups.

Affiliations:
Jeznach O. - IPPT PAN
Kołbuk D. - IPPT PAN
Marzec M. - other affiliation
Bernasik A. - other affiliation
Sajkiewicz P. - IPPT PAN
17.  Kołbuk D., Ciechomska M., Jeznach O., Sajkiewicz P., Effect of crystallinity and related surface properties on gene expression of primary fibroblasts, RSC Advances, ISSN: 2046-2069, DOI: 10.1039/D1RA07237D, Vol.12, No.7, pp.4016-4028, 2022

Abstract:
The biomaterial-cells interface is one of the most fundamental issues in tissue regeneration. Despite many years of scientific work, there is no clear answer to what determines the desired adhesion of cells and the synthesis of ECM proteins. Crystallinity is a characteristic of the structure that influences the surface and bulk properties of semicrystalline polymers used in medicine. The crystallinity of polycaprolactone (PCL) was varied by changing the molecular weight of the polymer and the annealing procedure. Measurements of surface free energy showed differences related to substrate crystallinity. Additionally, the water contact angle was determined to characterise surface wettability which was crucial in the analysis of protein absorption. X-ray photoelectron spectroscopy was used to indicate oxygen bonds amount on the surface. Finally, the impact of the crystallinity, and related properties were demonstrated on dermal fibroblasts' response. Cellular proliferation and expression of selected genes: α-SMA, collagen I, TIMP, integrin were analysed.

Affiliations:
Kołbuk D. - IPPT PAN
Ciechomska M. - National Institute of Geriatrics, Rheumatology and Rehabilitation (PL)
Jeznach O. - IPPT PAN
Sajkiewicz P. - IPPT PAN
18.  Dias Y.J., Robles J.R., Sinha-Ray S., Abiade J., Pourdeyhimi B., Niemczyk-Soczyńska B., Kołbuk D., Sajkiewicz P., Yarin A.L., Solution-blown poly(hydroxybutyrate) and ε-poly-l-lysine submicro- and microfiber-based sustainable nonwovens with antimicrobial activity for single-use applications, ACS BIOMATERIALS SCIENCE & ENGINEERING, ISSN: 2373-9878, DOI: 10.1021/acsbiomaterials.1c00594, Vol.7, No.8, pp.3980-3992, 2021

Abstract:
Antimicrobial nonwovens for single use applications (e.g., diapers, sanitary napkins, medical gauze, etc.) are of utmost importance as the first line of defense against bacterial infections. However, the utilization of petrochemical nondegradable polymers in such nonwovens creates sustainability-related issues. Here, sustainable poly(hydroxybutyrate) (PHB) and ε-poly-l-lysine (ε-PLL) submicro- and microfiber-based antimicrobial nonwovens produced by a novel industrially scalable process, solution blowing, have been proposed. In such nonwovens, ε-PLL acts as an active material. In particular, it was found that most of ε-PLL is released within the first hour of deployment, as is desirable for the applications of interest. The submicro- and microfiber mat was tested against C. albicans and E. coli, and it was found that ε-PLL-releasing microfibers result in a significant reduction of bacterial colonies. It was also found that ε-PLL-releasing antimicrobial submicro- and microfiber nonwovens are safe for human cells in fibroblast culture. Mechanical characterization of these nonwovens revealed that, even though they are felt as soft and malleable, they possess sufficient strength, which is desirable in the end-user applications.

Keywords:
PHB submicro- and microfibers, antimicrobial nonwovens, ε-PLL release, E. coli, C. albicans

Affiliations:
Dias Y.J. - other affiliation
Robles J.R. - other affiliation
Sinha-Ray S. - other affiliation
Abiade J. - other affiliation
Pourdeyhimi B. - other affiliation
Niemczyk-Soczyńska B. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Yarin A.L. - Technion-Israel Institute of Technology (IL)
19.  Bil M., Mrówka P., Kołbuk D., Święszkowski W., Multifunctional composite combining chitosan microspheres for drug delivery embedded in shape memory polyester-urethane matrix, Composites Science and Technology, ISSN: 0266-3538, DOI: 10.1016/j.compscitech.2020.108481, Vol.201, pp.108481-1-9, 2021

Abstract:
Multifunctional composite biomaterials (3b-PU/CH_M) consisting of chitosan microspheres (CH-M) that provide drug release functionality and crosslinked polyester-urethane (3b-PU) matrix responsible for shape memory properties were designed. A series of 3b-PU/CH_M bio-composites with varying weight fraction of CH-M (2.5, 5, and 10 wt %) embedded into 3b-PU matrix were synthesized. The ATR-FTIR confirmed the presence of covalent bonds between 3b-PU matrix and CH-M as well as enhanced hydrogen bonds interaction within bio-composites matrix in comparison to neat 3b-PU. It was found that CH-M had not impaired the shape memory properties of 3b-PU matrix and even slightly improved the shape recovery (Rr %). The Rr value increased to 100% for 3b-PU/CH 2.5% M and 3b-PU/CH 5% M after the third thermo-mechanical cycle. Moreover, the transition temperature (Ttrans) of shape recovery tailored to 30 °C by the chemical composition of the 3b-PU network was not affected by CH-M. Effectiveness of the application of the composites as a controlled drug delivery system at various pH conditions was confirmed in an in vitro release study of ciprofloxacin hydrochloride (Cpx-HCl) used as a model drug. In vitro biocompatibility studies revealed that the materials do not alter the cells' ability to proliferate and differentiate.

Keywords:
multifunctional composites, smart materials, shape memory behavior, multifunctional properties, drug release

Affiliations:
Bil M. - Warsaw University of Technology (PL)
Mrówka P. - other affiliation
Kołbuk D. - IPPT PAN
Święszkowski W. - other affiliation
20.  Niemczyk-Soczyńska B., Dulnik J., Jeznach O., Kołbuk D., Sajkiewicz P., Shortening of electrospun PLLA fibers by ultrasonication, Micron, ISSN: 0968-4328, DOI: 10.1016/j.micron.2021.103066, Vol.145, pp.103066-1-8, 2021

Abstract:
This research work is aimed at studying the effect of ultrasounds on the effectiveness of fiber fragmentation by taking into account the type of sonication medium, processing time, and various PLLA molecular weights. Fragmentation was followed by an appropriate filtration in order to decrease fibers length distribution. It was evidenced by fiber length determination using SEM that the fibers are shortened after ultrasonic treatment, and the effectiveness of shortening depends on the two out of three investigated parameters, mostly on the sonication medium, and processing time. The gel permeation chromatography (GPC) confirmed that such ultrasonic treatment does not change the polymers' molecular weight. Our results allowed to optimize the ultrasonic fragmentation procedure of electrospun fibers while preliminary viscosity measurements of fibers loaded into hydrogel confirmed their potential in further use as fillers for injectable hydrogels for regenerative medicine applications.

Keywords:
electrospinning, ultrasonication, short fibers, polymers

Affiliations:
Niemczyk-Soczyńska B. - IPPT PAN
Dulnik J. - IPPT PAN
Jeznach O. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
21.  Budnicka M., Kołbuk D., Ruśkowski P., Gadomska‐Gajadhur A., Poly‐L ‐lactide scaffolds with super pores obtained by freeze‐extraction method, Journal of Biomedical Materials Research Part B: Applied Biomaterials, ISSN: 1552-4973, DOI: 10.1002/jbm.b.34642, Vol.108, No.8, pp.3162-3173, 2020

Abstract:
A nonplanar polylactide scaffold to be used in tissue engineering was obtained by freeze‐extraction method. Properties of the scaffold were modified by adding Eudragit® E100. The impact of the modification on morphology, porosity and pore size, mass absorbability, mechanical properties was determined. Scanning electron microscopy (SEM), hydrostatic weighing test, static compression test was used to this end. The chemical composition of the scaffold was defined based on infrared spectroscopy (FTIR) and energy‐dispersive X‐ray spectroscopy (EDX). Biocompatibility was confirmed by quantitative tests and microscopic observation. The obtained results show that the obtained scaffolds may be applied as a carrier of hydrophilic cellular growth factors for more efficient tissue regeneration.

Keywords:
cellular studies, Eudragit® E100, freeze-extraction, poly-L-lactide

Affiliations:
Budnicka M. - other affiliation
Kołbuk D. - IPPT PAN
Ruśkowski P. - Warsaw University of Technology (PL)
Gadomska‐Gajadhur A. - Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences (PL)
22.  Górecka Ż., Idaszek J., Kołbuk D., Choińska E., Chlanda A., Święszkowski W., The effect of diameter of fibre on formation of hydrogen bonds and mechanical properties of 3D-printed PCL, Materials Science and Engineering C, ISSN: 0928-4931, DOI: 10.1016/j.msec.2020.111072, Vol.114, pp.111072-1-11, 2020

Abstract:
Fused Deposition Modelling (FDM) technique has been widely utilized in fabrication of 3D porous scaffolds for tissue engineering (TE) applications. Surprisingly, although there are many publications devoted to the architectural features of the 3D scaffolds fabricated by the FDM, none of them give us evident information about the impact of the diameter of the fibres on material properties. Therefore, the aim of this study was to investigate, for the first time, the effect of the diameter of 3D-printed PCL fibres on variations in their microstructure and resulting mechanical behaviour. The fibres made of poly(ε-caprolactone) (PCL) were extruded through commonly used types of nozzles (inner diameter ranging from 0.18 mm to 1.07 mm) by means of FDM technique. Static tensile test and atomic force microscopy working in force spectroscopy mode revealed strong decrease in the Young's modulus and yield strength with increasing fibre diameter in the investigated range. To explain this phenomenon, we conducted differential scanning calorimetry, wide-angle X-ray-scattering, Fourier-transform infrared spectroscopy, infrared and polarized light microscopy imaging. The obtained results clearly showed that the most prominent effect on the obtained microstructures and mechanical properties had different cooling and shear rates during fabrication process causing changes in supramolecular interactions of PCL. The observed fibre size-dependent formation of hydrogen bonds affected the crystalline structure and its stability. Summarising, this study clearly demonstrates that the diameter of 3D-printed fibres has a strong effect on obtained microstructure and mechanical properties, therefore should be taken into consideration during design of the 3D TE scaffolds.

Keywords:
fused deposition modelling, polycaprolactone, mechanical properties, hydrogen bonds, microstructure

Affiliations:
Górecka Ż. - Warsaw University of Technology (PL)
Idaszek J. - other affiliation
Kołbuk D. - IPPT PAN
Choińska E. - Warsaw University of Technology (PL)
Chlanda A. - Warsaw University of Technology (PL)
Święszkowski W. - other affiliation
23.  Budnicka M., Szymaniak M., Kołbuk D., Ruśkowski P., Gadomska-Gajadhur A., Biomineralization of poly-l-lactide spongy bone scaffolds obtained by freeze-extraction method, Journal of Biomedical Materials Research Part B: Applied Biomaterials, ISSN: 1552-4973, DOI: 10.1002/jbm.b.34441, Vol.108, No.3, pp.868-879, 2020

Abstract:
Implants in the form of polymer scaffolds are commonly used to regenerate bone tissue after traumas or tooth extractions. However, few implant formation methods enable building polymer scaffolds allowing to reconstruct larger bone losses without immune response. Spacious, porous poly-l-lactide implants with considerable volume were obtained using the phase inversion method with the freeze-extraction variant. The calcium phosphate (CaP) coating was deposited on implant surfaces with the biomimetic method to improve the implant's osteoconductivity. The substitues morphology was characterized-porosity, size and shape of pores; mechanical properties, mass absorbability of implants before and after mineralization. The characteristics were provided with scanning electron microscopy (SEM), static compression test and hydrostatic weighing, respectively. The presence of CaPs in the entire volume of the implant was confirmed with SEM and infrared spectroscopy with Fourier transform (FTIR). The biocompatibility of scaffolds was confirmed with in vitro quantitative test and microscopic observations. The obtained results show that the implants can be used in tissue engineering as a vehicle of platelet-rich plasma to regenerate critical spongy bone losses.

Keywords:
bone graft, calcium phosphate(s), cell culture

Affiliations:
Budnicka M. - other affiliation
Szymaniak M. - other affiliation
Kołbuk D. - IPPT PAN
Ruśkowski P. - Warsaw University of Technology (PL)
Gadomska-Gajadhur A. - Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences (PL)
24.  Kołbuk D., Jeznach O., Wrzecionek M., Gadomska-Gajadhur A., Poly(glycerol succinate) as an eco-friendly component of PLLA and PLCL fibres towards medical applications, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym12081731, Vol.12, No.8, pp.1731-1-17, 2020

Abstract:
This study was conducted as a first step in obtaining eco-friendly fibres for medical applications using a synthesised oligomer poly(glycerol succinate) (PGSu) as an additive for synthetic poly(L-lactic acid) (PLLA) and poly (L-lactide-co-caprolactone) (PLCL). The effects of the oligomer on the structure formation, morphology, crystallisation behaviour, and mechanical properties of electrospun bicomponent fibres were investigated. Nonwovens were investigated by means of scanning electron microscopy (SEM), wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), and mechanical testing. The molecular structure of PLLA fibres is influenced by the presence of PGSu mainly acting as an enhancer of molecular orientation. In the case of semicrystalline PLCL, chain mobility was enhanced by the presence of PGSu molecules, and the crystallinity of bicomponent fibres increased in relation to that of pure PLCL. The mechanical properties of bicomponent fibres were influenced by the level of PGSu present and the extent of crystal formation of the main component. An in vitro study conducted using L929 cells confirmed the biocompatible character of all bicomponent fibres.

Keywords:
poly(glycerol succinate), plasticiser, eco-friendly polymer, electrospinning, hyperbranched polyester

Affiliations:
Kołbuk D. - IPPT PAN
Jeznach O. - IPPT PAN
Wrzecionek M. - Warsaw University of Technology (PL)
Gadomska-Gajadhur A. - Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences (PL)
25.  Zaszczyńska A., Sajkiewicz P.Ł., Gradys A., Tymkiewicz R., Urbanek O., Kołbuk D., Influence of process-material conditions on the structure and biological properties of electrospun polyvinylidene fluoride fibers, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2020.133368, Vol.68, No.3, pp.627-633, 2020

Abstract:
Polyvinylidene fluoride (PVDF) is one of the most important piezoelectric polymers. Piezoelectricity in PVDF appears in polar β and ɣ phases. Piezoelectric fibers obtained by means of electrospinning may be used in tissue engineering (TE) as a smart analogue of the natural extracellular matrix (ECM). We present results showing the effect of rotational speed of the collecting drum on morphology, phase content and in vitro biological properties of PVDF nonwovens. Morphology and phase composition were analyzed using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), respectively. It was shown that increasing rotational speed of the collector leads to an increase in fiber orientation, reduction in fiber diameter and considerable increase of polar phase content, both b and g. In vitro cell culture experiments, carried out with the use of ultrasounds in order to generate electrical potential via piezoelectricity, indicate a positive effect of polar phases on fibroblasts. Our preliminary results demonstrate that piezoelectric PVDF scaffolds are promising materials for tissue engineering applications, particularly for neural tissue regeneration, where the electric potential is crucial.

Keywords:
scaffolds, electrospinning, polyvinylidene fluoride, tissue engineering

Affiliations:
Zaszczyńska A. - IPPT PAN
Sajkiewicz P.Ł. - IPPT PAN
Gradys A. - IPPT PAN
Tymkiewicz R. - IPPT PAN
Urbanek O. - IPPT PAN
Kołbuk D. - IPPT PAN
26.  Kołbuk D., Heljak M., Choińska E., Urbanek O., Novel 3D hybrid nanofiber scaffolds for bone regeneration, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym12030544, Vol.12, No.3, pp.544-1-18, 2020

Abstract:
Development of hybrid scaffolds and their formation methods occupies an important place in tissue engineering. In this paper, a novel method of 3D hybrid scaffold formation is presented as well as an explanation of the differences in scaffold properties, which were a consequence of different crosslinking mechanisms. Scaffolds were formed from 3D freeze-dried gelatin and electrospun poly(lactide-co-glicolide) (PLGA) fibers in a ratio of 1:1 w/w. In order to enhance osteoblast proliferation, the fibers were coated with hydroxyapatite nanoparticles (HAp) using sonochemical processing. All scaffolds were crosslinked using an EDC/NHS solution. The scaffolds' morphology was imaged using scanning electron microscopy (SEM). The chemical composition of the scaffolds was analyzed using several methods. Water absorption and mass loss investigations proved a higher crosslinking degree of the hybrid scaffolds than a pure gelatin scaffold, caused by additional interactions between gelatin, PLGA, and HAp. Additionally, mechanical properties of the 3D hybrid scaffolds were higher than traditional hydrogels. In vitro studies revealed that fibroblasts and osteoblasts proliferated and migrated well on the 3D hybrid scaffolds, and also penetrated their structure during the seven days of the experiment.

Keywords:
hybrid scaffolds, electrospinning, freeze-drying, gelatin, hydroxyapatite, sonochemical covering/grafting

Affiliations:
Kołbuk D. - IPPT PAN
Heljak M. - Warsaw University of Technology (PL)
Choińska E. - Warsaw University of Technology (PL)
Urbanek O. - IPPT PAN
27.  Auguścik-Królikowska M., Ryszkowska J., Szczepkowski L., Kwiatkowski D., Kołbuk-Konieczny D., Szymańska J., Viscoelastic polyurethane foams with the addition of mint, POLIMERY, ISSN: 0032-2725, DOI: 10.14314/polimery.2020.3.4, Vol.65, No.3, pp.196-207, 2020

Abstract:
The article presents an assessment of the possibilities of producing viscoelastic open cell polyurethane (PUR) foams produced with a natural filler in the form of mint leaves. PUR foams containing from 10 to 30 wt % of mint were produced. Chemical structure, thermal and mechanical properties of the foams were assessed. It was found that the filler containing 7 wt % of water caused significant changes in the foam characteristics. In composite foams, the content of urea and hydrogen bonds increased with higher mint contents. The hardness and comfort factor of composite foams also increased. The introduction of a filler containing a significant amount of water caused a change in the porosity and wall thickness of composite foams resulting in a significant increase in their permanent deformations.

Keywords:
open cell viscoelastic polyurethane foams, mint, cytocompatibility

Affiliations:
Auguścik-Królikowska M. - other affiliation
Ryszkowska J. - other affiliation
Szczepkowski L. - other affiliation
Kwiatkowski D. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
Szymańska J. - other affiliation
28.  Niemczyk-Soczyńska B., Gradys A., Kołbuk D., Krzton-Maziopa A., Sajkiewicz P., Crosslinking kinetics of methylcellulose qqueous solution and its potential as a scaffold for tissue engineering, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11111772, Vol.11, No.11, pp.1772-1-17, 2019

Abstract:
Thermosensitive, physically crosslinked injectable hydrogels are in the area of interests of various scientific fields. One of the representatives of this materials group is an aqueous solution of methylcellulose. At ambient conditions, methylcellulose (MC) is a sol while on heating up to 37 °C, MC undergoes physical crosslinking and transforms into a gel. Injectability at room temperature, and crosslinkability during subsequent heating to physiological temperature raises hopes, especially for tissue engineering applications. This research work aimed at studying crosslinking kinetics, thermal, viscoelastic, and biological properties of MC aqueous solution in a broad range of MC concentrations. It was evidenced by Differential Scanning Calorimetry (DSC) that crosslinking of MC is a reversible two-stage process, manifested by the appearance of two endothermic effects, related to the destruction of water cages around methoxy groups, followed by crosslinking via the formation of hydrophobic interactions between methoxy groups in the polymeric chains. The DSC results also allowed the determination of MC crosslinking kinetics. Complementary measurements of MC crosslinking kinetics performed by dynamic mechanical analysis (DMA) provided information on the final storage modulus, which was important from the perspective of tissue engineering applications. Cytotoxicity tests were performed using mouse fibroblasts and showed that MC at low concentration did not cause cytotoxicity. All these efforts allowed to assess MC hydrogel relevance for tissue engineering applications.

Keywords:
methylcellulose, thermosensitive hydrogel, crosslinking kinetics, DSC, DMA, cellular tests

Affiliations:
Niemczyk-Soczyńska B. - IPPT PAN
Gradys A. - IPPT PAN
Kołbuk D. - IPPT PAN
Krzton-Maziopa A. - Warsaw University of Technology (PL)
Sajkiewicz P. - IPPT PAN
29.  Jeznach O., Kołbuk D., Sajkiewicz P., Aminolysis of various aliphatic polyesters in a form of nanofibers and films, Polymers, ISSN: 2073-4360, DOI: 10.3390/polym11101669, Vol.11, No.10, pp.1669-1-16, 2019

Abstract:
Surface functionalization of polymer scaffolds is a method used to improve interactions of materials with cells. A frequently used method for polyesters is aminolysis reaction, which introduces free amine groups on the surface. In this study, nanofibrous scaffolds and films of three different polyesters–polycaprolactone (PCL), poly(lactide-co-caprolactone) (PLCL), and poly(l-lactide) (PLLA) were subjected to this type of surface modification under the same conditions. Efficiency of aminolysis was evaluated on the basis of ninhydrin tests and ATR–FTIR spectroscopy. Also, impact of this treatment on the mechanical properties, crystallinity, and wettability of polyesters was compared and discussed from the perspective of aminolysis efficiency. It was shown that aminolysis is less efficient in the case of nanofibers, particularly for PCL nanofibers. Our hypothesis based on the fundamentals of classical high speed spinning process is that the lower efficiency of aminolysis in the case of nanofibers is associated with the radial distribution of crystallinity of electrospun fiber with more crystalline skin, strongly inhibiting the reaction. Moreover, the water contact angle results demonstrate that the effect of free amino groups on wettability is very different depending on the type and the form of polymer. The results of this study can help to understand fundamentals of aminolysis-based surface modification.

Keywords:
aminolysis, polyester, electrospinning, nanofibers, film, surface chemical modification

Affiliations:
Jeznach O. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
30.  Kołbuk D., Urbanek O., Denis P., Choińska E., Sonochemical coating as an effective method of polymeric nonwovens functionalization, Journal of Biomedical Materials Research Part A, ISSN: 1549-3296, DOI: 10.1002/jbm.a.36751, Vol.107, No.11, pp.2447-2457, 2019

Abstract:
A surface of polymeric nonwovens may be coated with various types of nanoparticles for medical applications, filtration, and so forth. However, quite often methods used for surface modification are difficult to scale up or are not applicable for polymers. In this article, we present one-step process enabling nonwovens functionalization. Poly(l-lactide-co-glicolide) (PLGA) nonwovens were prepared by electrospinning process and coated with hydroxyapatite nanoparticles (HAp) using ultrasonic processing. The effect of the process was evaluated with various techniques. HAp layer was successfully attached without loss of structural properties of HAp or PLGA nonwovens. The analysis confirmed the decrease of hydrophobicity of coated nonwoven, as well as its biocompatibility, making this material valuable from the perspective of medical applications. The sonochemical functionalization of polymeric nonwovens may be considered as an effective and economic method, enhancing surface properties of electrospun nonwovens for various applications.

Keywords:
lectrospinning, fibrous composites, nanoparticles, surface modification, ultrasonic treatment

Affiliations:
Kołbuk D. - IPPT PAN
Urbanek O. - IPPT PAN
Denis P. - IPPT PAN
Choińska E. - Warsaw University of Technology (PL)
31.  Urbanek O., Kołbuk D., Wróbel M., Articular cartilage: new directions and barriers of scaffolds development – review, International Journal of Polymeric Materials and Polymeric Biomaterials, ISSN: 0091-4037, DOI: 10.1080/00914037.2018.1452224, Vol.68, No.7, pp.396-410, 2019

Abstract:
Despite progress which has been made in recent years in the field of cell-based therapies or cell scaffolds for cartilage regeneration, a lot of work still needs to be done. Scaffolds remain a great base for tissue regeneration. However, proper implantation procedures or post-treatment still await development. In this review we summarize paths of cartilage treatment, especially focusing on cell scaffold design and manufacture. As well as the advantages and disadvantages of available or investigated methods and materials, especially focusing on cartilage scaffold design. We show the most promising directions and barriers in the creation of healthy tissue.

Keywords:
cartilage regeneration, medical devices, scaffold development, tissue engineering

Affiliations:
Urbanek O. - IPPT PAN
Kołbuk D. - IPPT PAN
Wróbel M. - Centre for Specialized Surgery (PL)
32.  Zaszczyńska A., Sajkiewicz P., Gradys A., Kołbuk D., Urbanek O., Cellular studies on piezoelectric polyvinylidene fluoride nanofibers subjected to ultrasounds stimulations, ENGINEERING OF BIOMATERIALS / INŻYNIERIA BIOMATERIAŁÓW, ISSN: 1429-7248, Vol.22, No.153, pp.25-25, 2019
33.  Niemczyk B., Sajkiewicz P., Kołbuk D., Injectable hydrogels as novel materials for central nervous system regeneration, Journal of neural engineering, ISSN: 1741-2560, DOI: 10.1088/1741-2552/aacbab, Vol.15, No.5, pp.051002-1-15, 2018

Abstract:
Approach. Injuries of the central nervous system (CNS) can cause serious and permanent disability due to limited regeneration ability of the CNS. Presently available therapies are focused on lesion spreading inhibition rather than on tissue regeneration. Recent investigations in the field of neural tissue engineering indicate extremely promising properties of novel injectable and non-injectable hydrogels which are tailored to serve as biodegradable scaffolds for CNS regeneration. Objective. This review discusses the state-of-the-art and barriers in application of novel polymer-based hydrogels without and with nanoparticles for CNS regeneration. Main results. Pure hydrogels suffer from lack of similarities to natural neural tissue. Many of the biological studies indicated nano-additives in hydrogels may improve their topography, mechanical properties, electroconductivity and biological functions. The most promising biomaterials which meet the requirements of CNS tissue engineering seem to be injectable thermosensitive hydrogels loaded with specific micro-and nanoparticles. Significance. We highlight injectable hydrogels with various micro-and nanoparticles, because of novelty and attractiveness of this type of materials for CNS regeneration and future development perspectives.

Keywords:
hydrogels, nanoparticles, injectable, microparticles, nanofibers, central nervous system

Affiliations:
Niemczyk B. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Kołbuk D. - IPPT PAN
34.  Jeznach O., Kołbuk D., Sajkiewicz P., Injectable hydrogels and nanocomposite hydrogels for cartilage regeneration, Journal of Biomedical Materials Research Part A, ISSN: 1549-3296, DOI: 10.1002/jbm.a.36449, Vol.106, No.10, pp.2762-2776, 2018

Abstract:
Cartilage loss due to age‐related degeneration and mechanical trauma is a significant and challenging problem in the field of surgical medicine. Unfortunately, cartilage tissue can be characterized by the lack of regenerative ability. Limitations of conventional treatment strategies, such as auto‐, allo‐ and xenografts or implants stimulate an increasing interest in the tissue engineering approach to cartilage repair. This review discusses the application of polymer‐based scaffolds, with an emphasis on hydrogels in cartilage tissue engineering. We highlight injectable hydrogels with various micro‐ and nanoparticles, as they constitute a novel and attractive type of scaffolds. We discuss advantages, limitations and future perspectives of injectable nanocomposite hydrogels for cartilage tissue regeneration.

Keywords:
polymers, hydrogels, injectable hydrogels, injectable nanocomposite hydrogels, cartilage repair, cartilage tissue engineering

Affiliations:
Jeznach O. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
35.  Dulnik J., Kołbuk D., Denis P., Sajkiewicz P., The effect of a solvent on cellular response to PCL/gelatin and PCL/collagen electrospun nanofibres, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2018.05.010, Vol.104, pp.147-156, 2018

Abstract:
Bicomponent polycaprolactone/gelatin and polycaprolactone/collagen fibres were formed by electrospinning using two kinds of solvents: a representative of commonly used solvents with this polymer composition, highly toxic hexafluoroisopropanol (HFIP) and alternative, less harmful one, the mixture of acetic (AA) and formic (FA) acids. Both material types were subjected to investigations of structure and in-vitro cellular activity. Viscosity and Fourier transform infrared spectroscopy (FTIR) measurements shown that the type of solvent used influences the structure of solution and conformation of polymer molecules. In-vitro quantitative tests as well as cell culture morphology observations proved that materials electrospun with the use of 'green' solvents can yield similar results to those obtained by made with toxic ones. Slightly better cellular response to materials electrospun from HFIP can be explained by relatively well dispersed components within the fibre and more expanded conformation of molecules, resulting in better exposition of RGD (Arg-Gly-Asp) binding sites to cells' integrin receptors.

Keywords:
Cellular tests, Electrospinning, Biopolymers, Viscosity, Solvents

Affiliations:
Dulnik J. - IPPT PAN
Kołbuk D. - IPPT PAN
Denis P. - IPPT PAN
Sajkiewicz P. - IPPT PAN
36.  Enayati M.S., Behzad T., Sajkiewicz P., Rafienia M., Bagheri R., Ghasemi-Mobarakeh L., Kołbuk D., Pahlevanneshan Z., Bonakdar S.H., Development of electrospun poly (vinyl alcohol)-based bionanocomposite scaffolds for bone tissue engineering, Journal of Biomedical Materials Research Part A, ISSN: 1549-3296, DOI: 10.1002/jbm.a.36309, Vol.106, No.4, pp.1111-1120, 2018

Abstract:
The article is focused on the role of nanohydroxy apatite (nHAp) and cellulose nanofibers (CNFs) as fillers in the electrospun poly (vinyl alcohol) (ES-PVA) nanofibers for bone tissue engineering (TE). Fibrous scaffolds of PVA, PVA/nHAp (10 wt.%), and PVA/nHAp(10 wt.%)/CNF(3 wt.%) were successfully fabricated and characterized. Tensile test on electrospun PVA/nHAp10 and PVA/nHAp10/CNF3 revealed a three-fold and seven-fold increase in modulus compared with pure ES-PVA (45.45 ± 4.77). Although, nanofiller loading slightly reduced the porosity percentage, all scaffolds had porosity higher than 70%. In addition, contact angle test proved the great hydrophilicity of scaffolds. The presence of fillers reduced in vitro biodegradation rate in PBS while accelerates biomineralization in simulated body fluid (SBF). Furthermore, cell viability, cell attachment, and functional activity of osteoblast MG-63 cells were studied on scaffolds showing higher cellular activity for scaffolds with nanofillers. Generally, the obtained results confirm that the 3-componemnt fibrous scaffold of PVA/nHAp/CNF has promising potential in hard TE.

Keywords:
electrospinning, PVA bionanocomposites, scaffolds, bone tissue engineering, cell culture

Affiliations:
Enayati M.S. - Isfahan University of Technology (IR)
Behzad T. - Isfahan University of Technology (IR)
Sajkiewicz P. - IPPT PAN
Rafienia M. - Isfahan University of Medical Sciences (IR)
Bagheri R. - Isfahan University of Technology (IR)
Ghasemi-Mobarakeh L. - Isfahan University of Technology (IR)
Kołbuk D. - IPPT PAN
Pahlevanneshan Z. - Payame Noor University (IR)
Bonakdar S.H. - Pasteur Institute of Iran (IR)
37.  Urbanek O., Sajkiewicz P., Pierini F., Czerkies M., Kołbuk D., Structure and properties of polycaprolactone/chitosan nonwovens tailored by solvent systems, Biomedical Materials, ISSN: 1748-6041, DOI: 10.1088/1748-605X/aa5647, Vol.12, No.1, pp.015020-1-12, 2017

Abstract:
Electrospinning of chitosan blends is a reasonable idea to prepare fibre mats for biomedical applications. Synthetic and natural components provide, for example, appropriate mechanical strength and biocompatibility, respectively. However, solvent characteristics and the polyelectrolyte nature of chitosan influence the spinnability of these blends. In order to compare the effect of solvent on polycaprolactone/chitosan fibres, two types of the most commonly used solvent systems were chosen, namely 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and acetic acid (AA)/formic acid (FA). Results obtained by various experimental methods clearly indicated the effect of the solvent system on the structure and properties of electrospun polycaprolactone/chitosan fibres. Viscosity measurements confirmed different polymer–solvent interactions. Various molecular interactions resulting in different macromolecular conformations of chitosan influenced its spinnability and properties. HFIP enabled fibres to be obtained whose average diameter was less than 250 nm while maintaining the brittle and hydrophilic character of the nonwoven, typical for the chitosan component. Spectroscopy studies revealed the formation of chitosan salts in the case of the AA/FA solvent system. Chitosan salts visibly influenced the structure and properties of the prepared fibre mats. The use of AA/FA caused a reduction of Young's modulus and wettability of the proposed blends. It was confirmed that wettability, mechanical properties and the antibacterial effect of polycaprolactone/chitosan fibres may be tailored by selecting an appropriate solvent system. The MTT cell proliferation assay revealed an increase of cytotoxicity to mouse fibroblasts in the case of 25% w/w of chitosan in electrospun nonwovens.

Keywords:
chitosan, electrospinning, PCL/chitosan fibres, solvent system, chitosan salts

Affiliations:
Urbanek O. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Pierini F. - IPPT PAN
Czerkies M. - IPPT PAN
Kołbuk D. - IPPT PAN
38.  Dulnik J., Denis P., Sajkiewicz P., Kołbuk D., Choińska E., Biodegradation of bicomponent PCL/gelatin and PCL/collagen nanofibers electrospun from alternative solvent system, Polymer Degradation and Stability, ISSN: 0141-3910, DOI: 10.1016/j.polymdegradstab.2016.05.022, Vol.130, pp.10-21, 2016

Abstract:
Bicomponent polycaprolactone/gelatin and polycaprolactone/collagen nanofibers formed by electrospinning using various solvents were subjected to biodegradation and compared. Hexafluoroisopropanol (HFIP) was used as a reference solvent, while the second, alternative solvent system was the mixture of acetic acid (AA) with formic acid (FA). Biodegradation of investigated materials was manifested mainly by the gelatin leaching, including collagen which is indeed denaturated to gelatin during electrospinning, leading to nanofibers erosion. There was no molecular degradation of PCL during 90 days of biodegradation procedure as deduced from no change in the elongation stress at break. The rate of biopolymer leaching was very fast from all materials during the first 24 h of biodegradation, being related to surface leaching, followed by a slower rate leaching from deeper material layers. Mass measurements showed much faster biopolymer leaching from nanofibers electrospun from AA/FA than from HFIP because of strongly emulsive nature of the solution in the former case. Irrespective of the solvent used, the leaching rate increased with initial content of gelatin. The analysis of Young modulus during biodegradation indicated complex mechanism of changes, including biopolymer mass loss, increase of PCL crystallinity and partial gelatin renaturation.

Keywords:
Bicomponent nanofibers, Biodegradation, Biopolymer

Affiliations:
Dulnik J. - IPPT PAN
Denis P. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Kołbuk D. - IPPT PAN
Choińska E. - Warsaw University of Technology (PL)
39.  Kołbuk D., Guimond-Lischer S., Sajkiewicz P., Maniura-Weber K., Fortunato G., Morphology and surface chemistry of bicomponent scaffolds in terms of mesenchymal stromal cell viability, Journal of Bioactive and Compatible Polymers, ISSN: 0883-9115, DOI: 10.1177/0883911515621571, Vol.1, pp.1-14, 2016

Abstract:
Biological interaction between cells and scaffolds is mediated through events at surfaces. Proteins present in the culture medium adsorb on substrates, generating a protein adlayer that triggers further downstream events governing cell adhesion. Polymer blends often combine the properties of the individual components, for example, can provide mechanical as well as surface properties in one fibre. Therefore, mixtures of synthetic polycaprolactone and gelatin as a denatured form of collagen were electrospun at selected conditions and polymer weight ratios. Fibre morphologies and chemical properties of the surfaces were analysed. These scaffolds were seeded with human mesenchymal stromal cells and their viability was studied. Gelatin addition to polycaprolactone leads to a reduction in fibre diameter. A linear increase in gelatin at the fibre surface was observed in function of the weighed polymers, except for polycaprolactone/gelatin fibres incorporating equal weight ratios. Thereby, a depletion of gelatin at the fibre surface is stated for equally mixed polymers. The depletion of gelatin at the fibre surface is most probably due to hydrophobic interactions between hydrophobic segments of polycaprolactone and gelatin, affecting the spinning mechanism and thus fibre structure. Furthermore, polycaprolactone/gelatin blends show enhanced wettability properties compared to pure gelatin, at least partly due to molecular segregation. Results of in vitro studies reveal an increase in cellular viability and proliferation for cells cultivated on nanofibres containing gelatin, caused by the cell-attractive surface composition as well as the hydrophilic nature of the scaffolds. Contact guidance of cells seeded on parallelised fibres is observed, and DNA tests show evidently enhanced cell numbers on nanofibres containing 20 wt% of gelatin.

Keywords:
Mesenchymal stromal cells, electrospinning, surface, blends, biocompatibility, polymers, bioactivity

Affiliations:
Kołbuk D. - IPPT PAN
Guimond-Lischer S. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
Sajkiewicz P. - IPPT PAN
Maniura-Weber K. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
Fortunato G. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
40.  Latko P., Kołbuk D., Kozera R., Boczkowska A., Microstructural Characterization and Mechanical Properties of PA11 Nanocomposite Fibers, Journal of Materials Engineering and Performance, ISSN: 1059-9495, DOI: 10.1007/s11665-015-1817-2, Vol.25, No.1, pp.68-75, 2016

Abstract:
Polyamide 11/multi-walled carbon nanotubes nanocomposite fibers with weight fraction 2, 4, and 6 wt.% and diameter 80 μm were prepared with a twin screw mini-extruder. The morphology and degree of dispersion of the multi-walled carbon nanotubes in the fibers was investigated by using scanning and transmission electron microscopy. In turn, the molecular structure was indicated by using wide-angle x-ray scattering and correlated with thermal analysis. It was found that carbon nanotubes lead to the formation of α phase in the fibers and they show medial level of alignment within the length of the fiber. Mechanical analysis of the fibers shows that apart from the crystallinity content, the tensile strength is strongly dependent on the macroscopic defects of the surface of the fibers. Nanocomposite fibers based on polyamide 11 with carbon nanotubes can be used as a precursor for non-woven or woven fabrics manufacturing process.

Keywords:
aerospace, electron microscopy, nanomaterials, thermal analysis, x-ray

Affiliations:
Latko P. - other affiliation
Kołbuk D. - IPPT PAN
Kozera R. - other affiliation
Boczkowska A. - Warsaw University of Technology (PL)
41.  Kołbuk D., Guimond-Lischer S., Sajkiewicz P., Maniura-Weber K., Fortunato G., The Effect of Selected Electrospinning Parameters on Molecular Structure of Polycaprolactone Nanofibers, International Journal of Polymeric Materials and Polymeric Biomaterials, ISSN: 0091-4037, DOI: 10.1080/00914037.2014.945209, Vol.64, No.7, pp.365-377, 2015

Abstract:
The effect of electrospinning parameters on morphology, molecular, and supermolecular structure of polycaprolactone (PCL) fibers was analyzed, with respect to tissue engineering applications. Fibers morphology and structure are mainly determined by solution concentration and collector type. Applied voltage does not significantly influence supermolecular structure (crystallinity) and mechanical stiffness. There is correlation between changes in structure and proliferation of 3T3 cells as evidenced by in vitro study. Processing window of optimal scaffolds is relatively wide, however, variation of electrospinning parameters do not significantly affect their biological functionality.

Keywords:
3T3 cells, crystallinity, electrospinning, molecular orientation, polycaprolactone, porosity, tissue engineering

Affiliations:
Kołbuk D. - IPPT PAN
Guimond-Lischer S. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
Sajkiewicz P. - IPPT PAN
Maniura-Weber K. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
Fortunato G. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
42.  Sajkiewicz P., Kołbuk D., Electrospinning of gelatin for tissue engineering – molecular conformation as one of the overlooked problems, JOURNAL OF BIOMATERIALS SCIENCE, POLYMER EDITION, ISSN: 0920-5063, DOI: 10.1080/09205063.2014.975392, Vol.25, No.18, pp.2009-2022, 2014

Abstract:
Gelatin is one of the most promising materials in tissue engineering as a scaffold component. This biopolymer indicates biocompatibility and bioactivity caused by the existence of specific amino acid sequences, being preferred sites for interactions with cells, with high similarity to natural extracellular matrix. The present paper does not aspire to be a full review of electrospinning of gelatin and gelatin containing nanofibers as scaffolds in tissue engineering. It is focused on the still open question of the role of the higher order structures of gelatin in scaffold’s bioactivity/functionality. Gelatin molecules can adopt various conformations depending on temperature, solvent, pH, etc. Our review indicates the potential ways for formation of α-helix conformation during electrospinning and the methods of further structure stabilization. It is intuitively expected that the native α-helix conformation appearing as a result of partial renaturation of gelatin can be beneficial from the viewpoint of bioactivity of scaffolds, providing thus a much cheaper alternative approach as opposed to expensive electrospinning of native collagen.

Keywords:
gelatin, molecular conformation, electrospinning, nanofibers, scaffolds

Affiliations:
Sajkiewicz P. - IPPT PAN
Kołbuk D. - IPPT PAN
43.  Kołbuk D., Sajkiewicz P., Maniura-Weber K., Fortunato G., Structure and morphology of electrospun polycaprolactone/gelatine nanofibres, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2013.04.036, Vol.49, pp.2052-2061, 2013

Abstract:
Blends of polycaprolactone (PCL) and gelatine (Ge), being effective materials for tissue engineering strategies, were electrospun at various conditions and polymer weight ratios. The morphology, the supermolecular structure as well as the mechanical properties of resulting submicron sized fibres have been analyzed in relation to electrospinning conditions and PCL/Ge weight ratio. Compared to pure PCL, Ge addition leads to large reduction of fibre diameter and finally to changes of fibre morphology. For parallelised fibres collected on a rotating drum, preferred molecular orientation of PCL crystals is found. With increasing Ge content a general reduction of molecular orientation is observed. In addition, there is peculiar dependence of polycaprolactone crystallinity on the content of Ge, showing maximum at low Ge concentration (20%) as determined by differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). Such a trend can be explained by hydrophobic interactions in the system containing PCL, gelatine and water, being additional driving forces for crystallization of nonpolar PCL molecules. The presence of water within investigated blend systems has been evidenced experimentally using thermal gravimetric analysis (TGA). Young’s modulus of nonwovens, as determined by uniaxial tensile testing, indicates the effect of additivity of the stiffness of both polymers as well as the influence of preferred molecular orientation. Additional experiments were performed using collagen (Col) as a biopolymeric alternative to Ge. WAXS results show evidently amorphous structure of Col within the blended fibres, indicating strong tendency for denaturation of collagen into gelatine under the influence of hexafluoroisopropanol as a solvent.

Keywords:
Electrospinning, Nanofibres, Blend, Gelatine polycaprolactone, Molecular structure

Affiliations:
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Maniura-Weber K. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
Fortunato G. - Swiss Federal Laboratories for Materials Science and Technology (EMPA) (CH)
44.  Paprocki B., Szczepański J., Kołbuk D., Information transmission efficiency in neuronal communication systems, BMC NEUROSCIENCE, ISSN: 1471-2202, DOI: 10.1186/1471-2202-14-S1-P217, Vol.14(Suppl 1), No.P217, pp.1-2, 2013

Abstract:
The nature and efficiency of brain transmission pro-cesses, its high reliability and efficiency is one of the most elusive area of contemporary science [1]. We study information transmission efficiency by considering a neuronal communication as a Shannon-type channel. Thus, using high quality entropy estimators, we evaluate the mutual information between input and output signals. We assume model of neuron proposed by Levy and Baxter [2], which incorporates all essential qualitative mechanisms participating in neural transmission process.

Keywords:
transmission efficiency, neuronal communication, Shannon-type channe

Affiliations:
Paprocki B. - Kazimierz Wielki University (PL)
Szczepański J. - IPPT PAN
Kołbuk D. - IPPT PAN
45.  Kołbuk D., Sajkiewicz P., Denis P., Choińska E., Investigations of polycaprolactone/gelatin blends in terms of their miscibility, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.2478/bpasts-2013-0066, Vol.61, No.3, pp.629-632, 2013

Abstract:
Synthetic and natural polymers blends represent a new brand of materials with application in wound healing, scaffolds or drug delivery systems. Polycaprolactone/gelatin (PCL/Gt) blends were analyzed in terms of their miscibility. The PCL structure was investigated as a function of Gt content. Changes in the PCL spherulitic structure with Gt content were investigated by a polarizing-interference microscope. The analysis of the glass transition temperature (Tg) of both components as a function of PCL/Gt ratio by differential scanning calorimetry indicates that the system of polycaprolactone/gelatin belongs to a type of s.c. compatible system, being intermediate between miscible and immiscible systems. There is possibility of very limited miscibility of both components. Supplementary wide angle X-ray scattering results are presented.

Keywords:
lends, compatibility, miscibility, polycaprolactone, gelatin

Affiliations:
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Denis P. - IPPT PAN
Choińska E. - Warsaw University of Technology (PL)
46.  Kołbuk D., Sajkiewicz P., Kowalewski T.A., Optical birefringence and molecular orientation of electrospun polycaprolactone fibers by polarizing-interference microscopy, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2011.11.012, Vol.48, pp.275-283, 2012

Abstract:
The potential of polarizing-interference Pluta microscope for determination of optical birefringence of individual nanofibers formed by electrospinning was shown. This technique can be applied for measurements of fiber birefringence, practically at diameter above 300 nm. The molecular orientation of individual polycaprolactone (PCL) nanofibers was determined from birefringence assuming the same orientation of both phases, crystal and amorphous. The molecular orientation was determined using DSC crystallinity, crystal intrinsic birefringence calculated for the first time for PCL from bond polarizabilities as well as estimated value of amorphous intrinsic birefringence. Our results indicate that the birefringence and thus molecular orientation are strongly inhomogeneous along the nanofibers, reflecting a complex nature of forces acting during electrospinning process. The average molecular orientation is weak if any, being dependent together with fiber thickness and crystallinity on electrospinning parameters, like applied voltage, concentration and type of solvent. The obtained results indicate that the average molecular orientation displays similar dependence on applied voltage as fiber diameter. Relatively low melting temperature of electrospun nanofibers suggests low crystal size and/or high concentration of defects in crystals. This observation corresponds with low crystallinity and molecular orientation, indicating together relatively low degree of crystal ordering due to high rate of cooling and solvent evaporation during electrospinning, limiting thus crystallization process.

Keywords:
Nanofibers, Electrospinning, Birefringence, Polarizing-interference microscopy, Polycaprolactone

Affiliations:
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Kowalewski T.A. - IPPT PAN

List of chapters in recent monographs
1. 
Kołbuk D., Nanofiber Research - Reaching New Heights, rozdział: Tailoring of Architecture and Intrinsic Structure of Electrospun Nanofibers by Process Parameters for Tissue Engineering Applications, Intechopen, -, pp.56-87, 2016

Conference papers
1.  Kołbuk D., Denis P., Choińska E., Sajkiewicz P., Investigations of polycaprolactone/gelatine blends in terms of their miscibility, 3rd Polish Conference on Nano- and Micromechanics, 2012-07-04/07-07, Warszawa (PL), Vol.1, pp.135-137, 2012
2.  Kołbuk D., Kowalewski T.A., Sajkiewicz P., Optical investigations of structure of poly(caprolactone) nanofibers formed by electrospinning, 1st Polish Conference on Nano- and Micromechanics, 2008-07-08/07-12, Krasiczyn (PL), pp.107-108, 2008

Conference abstracts
1.  Jeznach O., Dulnik J., Moczulska-Heljak M., Kołbuk-Konieczny D., BIODEGRADABLE SCAFFOLD FOR ANTERIOR CRUCIATE LIGAMENT (ACL) RECONSTRUCTION AND REGENERATION, NANOBIOMEDICA 2023, I Ogólnopolska Konferencja NanoBioTechMedyczna, 2023-09-21/10-22, Warszawa (PL), pp.40, 2023
2.  Dulnik J., Kołbuk-Konieczny D., Moczulska-Heljak M., 3D PRINTED BIODEGRADABLE SCAFFOLD FOR OPTIMAL RESTORATION OF KNEE FUNCTIONALITY AFTER AN ACL INJURY - A DEGRADATION AND STABILITY STUDY, ICSAAM 2023, The 10th International Conference on Structural Analysis of Advanced Materials, 2023-09-10/09-14, Zakyntos (GR), pp.1, 2023
3.  Jeznach O., Sajkiewicz P., Kołbuk-Konieczny D., Reich T., Dulnik J., GELATIN IMMOBILIZATION ON ELECTROSPUN ALIPHATIC POLYESTER FIBERS FOR TISSUE ENGINEERING, Tissue Engineering Part A, ISSN: 1937-3341, DOI: 10.1089/ten.tea.2023.29046.abstracts, pp.859-860, 2023
4.  Niemczyk-Soczyńska B., Kołbuk-Konieczny D., Mikułowski G., Rogujski P., Stanaszek L., Sajkiewicz P., INJECTABLE THERMOSENSITIVE METHYLCELLULOSE/AGAROSE HYDROGEL AS SMART SCAFFOLD FOR TISSUE ENGINEERING APPLICATIONS, Tissue Engineering Part A, ISSN: 1937-3341, DOI: 10.1089/ten.tea.2023.29046.abstracts, pp.631, 2023
5.  Jeznach O., Kołbuk D., Sajkiewicz P., Immobilization of gelatin on electrospun fibers: a comparative analysis of aminolysis-based procedure and physisorption for three aliphatic polyesters, ESB 2021, 31st Annual Conference of the European Society for Biomaterials, 2021-09-05/09-09, Porto (PT), pp.1929, 2021
6.  Jeznach O., Kołbuk D., Sajkiewicz P., Impact of surface modification on polyester nanofibers properties and scaffold-cells interaction, WBC2020, 11th World Biomaterials Congress, 2020-12-11/12-15, online (GB), pp.1-2, 2020

Keywords:
coatings, fibre-based biomaterials incl. electrospinning, material/tissue interfaces

Affiliations:
Jeznach O. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
7.  Jeznach O., Kołbuk D., Sajkiewicz P., Surface modification of polymer fibers based on aminolysis and gelatin immobilization as a method of improvement of cell-scaffold interaction, UK-Poland Bioinspired Materials Conference, 2020-11-23/11-24, Lancaster (GB), pp.77, 2020
8.  Kołbuk-Konieczny D., Urbanek-Świderska O., Jeznach O., Hybrid scaffold to anterior cruciate ligament regeneration, TERMIS EU 2019, TERMIS European Chapter Meeting 2019, Tissue Engineering Therapies: From Concept to Clinical Translation & Commercialisation, 2019-05-27/05-31, Rodos (GR), pp.1461, 2019
9.  Urbanek-Świderska O., Kołbuk D., Designing of Three-Dimensional Hybrid Scaffolds for Tissue Regeneration, 2019 MRS FALL MEETING & EXHIBIT, 2019-12-01/12-06, Boston (US), pp.1659, 2019
10.  Sajkiewicz P., Jeznach O., Kołbuk-Konieczny D., Functionalization of Aliphatic Polyester Fibers Formed by Electrospinning - The Effect of Crystallinity on Aminolysis, BIOMATSEN, 4th International Congress on Biomaterials and Biosensors, 2019-05-12/05-18, Fethiye (TR), No.Id-289, pp.96-97, 2019

Keywords:
Nanofibers, polyesters, surface functionalization, aminolysis, structure

Affiliations:
Sajkiewicz P. - IPPT PAN
Jeznach O. - IPPT PAN
Kołbuk-Konieczny D. - IPPT PAN
11.  Zaszczyńska A., Sajkiewicz P., Gradys A., Kołbuk D., Urbanek O., Cellular studies of piezoelectric nanofibers with ultrasound stimulations, Aerogels Processing, Modelling and Environmental-Driven Applications, 2019-10-21/10-23, Coimbra (PT), No.P04, pp.36, 2019
12.  Jeznach O., Kołbuk D., Sajkiewicz P., Surface functionalization of polyesters nanofibers via aminolysis and gelatin immobilization, TERMIS EU 2019, TERMIS European Chapter Meeting 2019, Tissue Engineering Therapies: From Concept to Clinical Translation & Commercialisation, 2019-05-27/05-31, Rodos (GR), pp.1606, 2019
13.  Zaszczyńska A., Sajkiewicz P., Gradys A., Urbanek O., Kołbuk D., Influence of process-material conditions on the phase composition, architecture and biological properties of electrospun polyvinylidene fluoride fibers, CNM 2019, 6th CONFERENCE ON NANO- AND MICROMECHANICS, 2019-07-03/07-05, Rzeszów (PL), pp.145-147, 2019

Keywords:
scaffolds, electrospinning, polyvinylidene fluoride, tissue engineering

Affiliations:
Zaszczyńska A. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Gradys A. - IPPT PAN
Urbanek O. - IPPT PAN
Kołbuk D. - IPPT PAN
14.  Jeznach O., Kołbuk D., Sajkiewicz P., Immobilization of gelatin on electrospun polyesters nanofibers to enhance biological response, EYEC2019, 8th European Young Engineers Conference, 2019-04-08/04-10, Warszawa (PL), pp.266, 2019

Keywords:
polymers, aminolysis, surface modification, tissue engineering

Affiliations:
Jeznach O. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
15.  Jeznach O., Wrzecionek M., Ruskowski P., Gadomska-Gajadhur A., Kołbuk D., Effect of poly(glycerol succinate) addition on properties of PLA electrospun fibres, ESB2018, 29th European Conference on Biomaterials, 2018-09-09/09-13, Maastricht (NL), pp.1084-1085, 2018
16.  Kołbuk-Konieczny D., Selected microenvironmental and material factors deciding about scaffold efficiency, PICETE, Polish-Israeli Conference on Electrospinning and Tissue Engineering, 2018-10-04/10-05, Warszawa (PL), pp.19, 2018
17.  Urbanek O., Kołbuk D., Sonochemical modification of electrospun fibres with hydroxyapatite nanoparticles, ESB2018, 29th European Conference on Biomaterials, 2018-09-09/09-13, Maastricht (NL), pp.523-524, 2018
18.  Sajkiewicz P., Dulnik J., Kołbuk-Konieczny D., Denis P., Structure dependent cell activity on pcl/gelatin and pcl/collagen nanofibers electrospun from various solvents, Electrospin2018 International Conference, 2018-01-16/01-18, Stellenbosch (ZA), pp.45-46, 2018
19.  Sajkiewicz P., Dulnik J., Kołbuk-Konieczny D., Denis P., The effect of solvent-polymer interactions on cellular response of electrospun PCL/gelatin and PCL/collagen fibers, ESB 2017, 28th European Conference on Biomaterials, 2017-09-04/09-08, Ateny (GR), pp.1, 2017
20.  Dulnik J., Kołbuk D., Denis P., Sajkiewicz P., Cellular studies of electrospun PCL/biocomponent nanofibers from alternative and traditional solvents, TERMIS-EU 2017, European Chapter Meeting of the Tissue Engineering and Regenerative Medicine International Society 2017, 2017-06-26/06-30, Davos (CH), pp.P715-P715, 2017
21.  Dulnik J., Denis P., Sajkiewicz P., Kołbuk D., Bicomponent PCL/Biopolymer nanofibers electrospun from various solvents - cellular and biodegradation studies, ELECTROSPIN 2016, 4th International Conference on Electrospinning, 2016-06-28/07-01, Otranto (IT), pp.1, 2016

Abstract:
Electrospun nonwovens from PCL/gelatin and PCL/collagen structurally mimic native extracellular matrix and provide cells with chemical cues affecting them. Electrospinning of bicomponent nanofibres requires the use of a solvent which dissolves both of the polymers.
We have optimized the process of electrospinning of PCL/gelatin and PCL/collagen nanofibers based on the use of non-toxic, alternative solvents: acetic acid and formic acid (AA/FA) as previously described [1].
Bicomponent PCL/gelatin and PCL/collagen nanofibers were formed by electrospinning using the mixture of acetic acid and formic acid (9:1 w/w ratio), while hexafluoroisopropanol (HFIP) was used as a reference solvent. Nonwoven materials were subjected to cellular in vitro and biodegradation tests and compared.
All in vitro tests were performed using L929 mouse fibroblast cells. Cytotoxicity test was carried out on extracts and showed that all type of materials are not cytotoxic. Materials with 10% biopolymer content as well as made from PCL only underwent experiment in direct contact. Cells were cultured on materials for 3, 5 and 7 days and afterwards taken for SEM as well as fluorescent dying of nuclei and cytoskeleton. Obtained results proved that the addition of Arg-Gly-Asp (RGD) amino acid sequences from biopolymer, in comparison to pure PCL materials, facilitates cell adhesion and spreading on the surface of nonwovens regardless of solvent used in electrospinning.
PCL/gelatin and PCL/collagen nonwovens underwent biodegradation in PBS solution at 37°C. After different times, ranging from 1 to 90 days samples were subjected for comparative analysis via various methods.
Despite the fact that bicomponent nanofibers electrospun from alternative solvents have similar morphology to those electrospun from perfluorinated alcohols, they differ in the internal structure which seriously affects biodegradation process. Biodegradation of investigated materials is manifested mainly by the gelatin leaching, which leads to nanofibers erosion, particularly large for nanofibers spun from AA/FA.

Keywords:
electrospinning, bicomponent nanofibers, biodegradation, cellular studies

Affiliations:
Dulnik J. - IPPT PAN
Denis P. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Kołbuk D. - IPPT PAN
22.  Kołbuk D., Denis P., Urbanek O., Tailoring of mechanical properties by molecular orientation in polymeric scaffolds, BioMaH, BIOMATERIALS FOR HEALTHCARE: Biomaterials for Tissue and Genetic Engineering and the Role of Nanotechnology, 2016-10-17/10-20, Rzym (IT), pp.443-446, 2016

Keywords:
molecular orientation, scaffolds, fibres, tissue engineering

Affiliations:
Kołbuk D. - IPPT PAN
Denis P. - IPPT PAN
Urbanek O. - IPPT PAN
23.  Urbanek o., Kołbuk D., Sajkiewicz P., Cellular Response on Polycaprolactone/Chitosan Crystalinity Tailored by Solvent System in Electrospinning Process, PUZZLE 2015, IV Wrocławska Konferencja Studentów Nauk Technicznych i Ścisłych, 2015-04-18/04-19, Wrocław (PL), pp.22, 2015

Keywords:
chitosan, PCL, cellular responce, electrospinning

Affiliations:
Urbanek o. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
24.  Urbanek O., Kołbuk D., Sajkiewicz P., Odpowiedź komórkowa na krystaliczność włókien polikaprolakton/ chitozan uzyskiwaną z wybranych rozpuszczalników, XIX Krajowa Konferencja Biocybernetyka i Inżynieria Biomedyczna, 2015-10-14/10-16, Warszawa (PL), pp.213, 2015

Keywords:
chitozan, polikaprolakton, electrospinning, L929, cytotoksyczność

Affiliations:
Urbanek O. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
25.  Urbanek O., Pierini F., Kołbuk D., Sajkiewicz P., Effect of positive and negative charge applied during electrospinning on surface chemistry and selected properties of chitosan nanofibers, COST MP1206 Workshop on Electrospinning of Chitosan, 2015-09-02/09-03, Münster (DE), pp.7-8, 2015

Keywords:
electrospinning, fibres, surface, chitosan

Affiliations:
Urbanek O. - IPPT PAN
Pierini F. - IPPT PAN
Kołbuk D. - IPPT PAN
Sajkiewicz P. - IPPT PAN
26.  Kołbuk D., Denis P., Bil M., Sajkiewicz P., Influence of Crystallinity and Selected Mechanical Properties on Cellular Response, ICMAT2015, 8th International Conference on Materials for Advanced Technologies and IUMRS – International Conference in Asia, 2015-06-28/07-03, Suntec (SG), pp.M-PO2, 2015

Abstract:
Cells sense subtract stiffness, elasticity and transduce that information into morphological changes and lineage specification. Polymer molecular order and mechanical properties, specially stiffness and elasticity indicate influence on cellular response during in- vitro study [e.g. Bershadskye et al 2013]. The aim of proposed presentation is to evaluate the effect of tailored crystallinity and mechanical properties of one- and bicomponent polymer films in terms of cells morphology and proliferation without changing other parameters. Polycaprolactone (PCL) and Gelatin (Ge) were used. As a solvents: Hexafluoroisopropanole (H), Acetic Acid (AA) were chosen. Two methods of foil preparation were analysed: forming from melt (onecomponent), forming from solution (one- and bicomponent).In both methods, the degree of crystallinity was modified mainly by the different type of PCL molecular weight, solvent type and/or annealing. Films were analysed using polarizinginterference microscopy allowing characterization of spherulities morphology. Degree of crystallinity was analysed by differential scanning calorimetry. Foils topography was analysed by atomic force microscopy, selected mechanical properties and hydrophilicity (contact angle) as the significant from the viewpoint of cellular activity were determined as well. L929 cells adhesion and morphology ware analysed by immunohistochemical staining for actin and nuclei. Cell activity and proliferation were analysed also. It is evident that conditions of PCL films preparation affect the morphology of spherulites. All samples were birefringent, indicating in general crystallinity, being different for particular samples. Maltese cross was observed in few samples. Crystallinity of PCL films determined from DSC measurements was in range 0,45-0,70 depending on solvent and polymer molecular weight used. Young Modulus strongly depends on Mw of PCL and Ge additive. L929 cells interact with subtract; morphology and proliferation degree change with crystallinity and elasticity of one- and bicomponet films.

Keywords:
crystallinity, PCL, mechanical properties, casted films

Affiliations:
Kołbuk D. - IPPT PAN
Denis P. - IPPT PAN
Bil M. - Warsaw University of Technology (PL)
Sajkiewicz P. - IPPT PAN
27.  Dulnik J., Denis P., Sajkiewicz P., Kołbuk D., Biodegradation of bicomponent PCL/Gelatin nanofibres electrospun from alternative solvent system. Structure and properties analysis, Electrospun Nano- and Microfibres for Biomedical Applications Conference, 2015-08-31/09-03, Eger (HU), pp.1, 2015

Abstract:
Bicomponent polycaprolactone/gelatin nanofibers were formed by electrospinning as previously described [1] using a novel polymer – solvent system with solvents being alternative to the commonly used toxic solvents like fluorinated alcohols. PCL/Gelatin nanofibres were electrospun from the mixture of acetic acid (AA) with formic acid (FA) (90:10) and from hexafluoroisopropanol (HFIP), that was used as reference solvent. PCL/Gelatin nanofibres with polymers w/w ratios 9:1, 8:2 and 7:3, underwent biodegradation in PBS solution at 37°C. After different times, ranging from 1 to 90 days, they were rinsed in demineralized water and dried. Weight loss and FTIR tests were performed to assess the kinetics of gelatin leaching, while SEM imaging and hydrophobicity tests to show its depletion from the surface. DSC measurements were carried out to examine changes in fibres’ internal structure and uniaxial tensile testing to compare their mechanical properties. Morphology of PCL/Gt fibers obtained from AA/FA is similar to that obtained from HFIP. Despite similar morphology, the internal structure of nanofibers formed from alternative solvents is different, reflecting the emulsive nature of PCL/gelati n mixture in AA/FA solvents contrary to clear, transparent solutions in HFIP. This apparent difference affects strongly the kinetics of leaching of gelatin from bicomponent fibres and thus how their mechanical and bioactive properties are changing in time after placing in living organism. There is substantial difference in kinetics of gelatin leaching depending on solvent used. Mass measurements show much faster gelatin degradation in nanofibres electrospun from AA/FA than from HFIP. For instance, for PCL/Gt 7:3 samples, gelatin content loss is 85% for AA/FA and 68% for HFIP after 90 days. Moreover, irrespective of the solvent used, the degradation rate increases with initial content of gelatin and is the highest in the first 24 hours: 27% for AA/FA 9:1 and 67% for 7:3 and 13% and 32% for HFIP respectively. The observed changes can be explained by nonuniform distribution of gelatin within fibres spun form AA/FA due to emulsive character of solution. Comparison of SEM images reveals linear groove-like sites remaining after gelatin leaching on a surface of fibres spun from AA/FA solvent. Contrary to this, fibres spun from HFIP remain smooth which can be attributed to molecular dispersion of both components.

Keywords:
nanofibers, biodegradation, polycaprolactone, gelatin

Affiliations:
Dulnik J. - IPPT PAN
Denis P. - IPPT PAN
Sajkiewicz P. - IPPT PAN
Kołbuk D. - IPPT PAN
28.  Urbanek O., Kucharska M., Dulnik J., Kołbuk D., Bicomponent nanofibers in tissue engineering, Szkoła Zimowa, 2014-12-15/12-16, Warszawa (PL), pp.30, 2014

Abstract:
Bicomponent poly(caprolactone)/ chitosan (PCL/Chit) nanofibers are a promising alternative for cartilage tissue regeneration. Chitosan is characterized by high structural similarity to the glycosaminoglycans (GAG) which naturally occur in the extracellular matrix (ECM). Its hydrophilicity is beneficial for cells adhesion and proliferation [1]. The amino groups in chitosan are responsible for the formation of polycations, which subsequently form compounds with natural and synthetic anions (proteins, lipids, synthetic polymers which are negatively charged) [2, 3]. Electrospinning of polycations with positive charge on the needle, is difficult due to the instability of the stream resulting from large repulsion force in the polymer jet [3]. Introduction of synthetic polymer molecules to the solution decreases interactions between the chains of chitosan and reduces the viscosity of the solution, so they are easier to form by electrospinning, as well as with negative charge on the needle [4 ]. A synthetic polymer, which is poly(caprolactone), improves mechanical properties of the fibers and the time of the hydrolytic degradation of the scaffold [4]. Nanofibers are excellent material for cell scaffolds used in tissue engineering because of high similarity of their morphology to native extracellular matrix (ECM) [1, 2]. From the viewpoint of cartilage tissue regeneration scaffold in the form of nanofibers is particularly justified due to naturally occurring network of polymer fibers (proteins and glycosaminoglycans) called aggrecans, in ECM of cartilage. Chondrocytes are connected with aggrecans [4]. Both, the structure and composition of formed nanofibers may affect the time in which cells will reach their proper morphology and undertake its functions [4]. In order to study cell behavior on electrospun PCL/chitosan nonwoven, fibroblasts L929 were cultured. Actin Green staining was conducted in order to imagine actin cytoskeleton of fibroblasts. To characterize, both fibers structure and cell morphology, SEM imagining was done. AFM imaging was carried to describe fibers topography and phase distribution. Also conductivity and viscosity of the PCL/chitosan solution with various polymer ratio was measured.

Keywords:
electrospinninig, scaffolds, PCL, chitozan, cellular responce

Affiliations:
Urbanek O. - IPPT PAN
Kucharska M. - IPPT PAN
Dulnik J. - IPPT PAN
Kołbuk D. - IPPT PAN
29.  Kołbuk D., Denis P., Urbanek O., L929 response on polycaprolactone films with tailored crystallinity, Szkoła Zimowa, 2014-12-15/12-16, Warszawa (PL), pp.29, 2014

Abstract:
Influence of the crystallinity of the substrate on cell proliferation during in-vitro study was highlighted in few articles. Methods of forming 3-D scaffolds usually do not take into account crystallinity optimisation. The aim of proposed presentation is to investigate an influence of polycaprolactone (PCL) crystallinity on cells spreading, their activity and proliferation. PCL Mn 45k and Mn 80k g/mol were used. As a solvents: HFIP (H) and Acetic Acid (AA) were used. Two methods of foil preparation were analysed: -forming from melt (PCL45, PCL80) -forming from 10%wt solution (e.g. PH45, PAA45) Samples were analyzed using interfered-polarization microscopy (MIP) which allows to describe the morphology of spherolites (crystalline and amorphous phase). Degree of crystallinity was analysed by differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). Selected samples surfaces were O2 plasma treated to decrease hydrophobic properties of PCL. L929 cells adhesion and morphology were analyzed by immunohistochemical staining for actin and nuc lei. Cell activity and proliferation were analyzed. Morphology of spherolites was analyses using interfered-polarization microscopy (MIP). Analyses indicate changes in spherolites shape, size and also crystalline/ amorphous phase amount. Differences of crystallinity for PCL using different molecular weight were analysed by DSC and WAXS measurements. Decrease of contact angle was observed for O2 plasma treated samples. All PCL films were found as nontoxic for L929 cells. Differences in cells spreading, activity and proliferation degree were found. Modification of Mn, solvent and concentration of PCL enable film formation in wide range of crystallinity. L929 during in-vitro study interact with the PCL film. Crystallinity as part of the supermolecular structure influence on cells morphology.

Keywords:
crystallinity, PCL, cellular responce, structure

Affiliations:
Kołbuk D. - IPPT PAN
Denis P. - IPPT PAN
Urbanek O. - IPPT PAN
30.  Kołbuk D., Denis P., Choińska E., Sajkiewicz P., Tailoring of polycaprolactone crystallinity, E-MRS FALL MEETING 2014, 2014-09-15/09-18, Warszawa (PL), pp.91, 2014

Abstract:
Introduction In the case of semicrystalline polymers, crystallinity is the parameter determining their physical properties. Some research groups indicate influence of crystallinity on cells response during in- vitro study. Commonly used methods of three-dimensional scaffolds formation do not take into account crystallinity optimisation. The aim of proposed presentation is to evaluate the effect of molecular weight and solvent on crystallinity and crystal size in case of polycaprolactone (PCL) films. Methodology Material: PCL with Mn:10, 45 and 80k g/mol (Sigma Aldrich) was used. As a solvents: Hexafluoroisopropanole, HFIP (Iris Biotech GmbH.), Acetic Acid, AA and Dichloromethane, DCM (Avantor and Chempol respectively) were used. Methods: Films were prepared from the PCL with different molecular weight using various solvents differing in evaporation rate. Characterization: Films were analysed using polarizing-interference microscopy (MPI) allowing characterization ofspherulities morphology. Degree of crystallinity was analysed by differential scanning calorimetry (DSC) and comparatively bywide angle X-ray scattering (WAXS). Results and Discussion It is evident from MPI observations that conditions of PCL films preparation affect the morphology of spherulites. All samples were birefringent, indicating in general crystallinity, being different for particular samples. Sphorulities size depends on Mw and solvent type; sharp Maltese cross was observed on few samples. Crystallinity of PCL films determined from DSC measurements was in the range 0,45-0,68 depending on solvent and polymer Mn used. Generally crystallinity of films formed from DCM is lower than from AA as a result of lower boiling point of DCM. Additional annealing enables increase in crystallinity to 0,8. WAXS crystallinity correlates with values determined by DSC. Changes of full width of half maximum(FWHM) of crystal peaks indicate variations of crystal size and/or defects depending on molecular weight and solvent what correlates with MPI observations also. Conclusions spherulites shape and crystallinity are strongly dependent on Mn and solvent type. Structural parameters of films decide on Young modulus and elasticity in terms of applications

Keywords:
crystallinity, PCL, solvents WAXS, molecular structure

Affiliations:
Kołbuk D. - IPPT PAN
Denis P. - IPPT PAN
Choińska E. - Warsaw University of Technology (PL)
Sajkiewicz P. - IPPT PAN
31.  Kołbuk D., Denis P., Dulnik J., Sajkiewicz P., Modifications of polycaprolactone films crystallinity in terms of tissue engineering applications, 20th Swiss Conference on Biomaterials and Regerative Medicine, 2014-05-07/05-08, Basel (CH), Vol.28, No.6, pp.30, 2014

Abstract:
Few research groups have highlighted the unexpected degree of cell proliferation depending on the degree of crystallinity of the substrate. Commonly used methods of forming three-dimensional scaffolds do not take into account crystallinity optimisation.
The aim of proposed presentation is to investigate polycaprolactone (PCL) substrate supermolecular structure effect, mainly crystallinity, on cells spreading, activity and proliferation.

Keywords:
crystalllinity, PCL, solvent, molecular structure, L929

Affiliations:
Kołbuk D. - IPPT PAN
Denis P. - IPPT PAN
Dulnik J. - IPPT PAN
Sajkiewicz P. - IPPT PAN

Patents
Filing No./Date
Filing Publication
Autors
Title
Protection Area, Applicant Name
Patent Number
Date of Grant
pdf
448460
2024-04-30
-
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Kołbuk-Konieczny D., Wróbel M., Dulnik J., Moczulska-Heljak M., Jeznach O.
Implant do rekonstrukcji więzadeł o strukturze porowatej oraz sposób jego wytwarzania
PL, Instytut Podstawowych Problemów Techniki PAN
-
-
-
443405
2023-01-03
BUP 28/2024
2024-07-08
Altangerel A., Kołbuk-Konieczny D., Sajkiewicz P. Ł.
Nośnik współdostarczania substancji reagujący na różne temperatury w formie włókniny typu Janus oraz sposób jego wytwarzania i zastosowanie
PL, Instytut Podstawowych Problemów Techniki PAN
-
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430802
2019-08-02
BUP 03/2021
2021-02-08
Gadomska-Gajadhur A., Budnicka M., Ruśkowski P., Kołbuk-Konieczny D.
Method of obtaining polylactide substitute for cancellous bone
PL, Politechnika Warszawska
239154
WUP 32/2021
2021-11-08



426830
2018-08-28
BUP 06/2020
2020-03-09
Gadomska-Gajadhur A., Ruśkowski P., Synoradzki L., Wrzecionek M., Kołbuk-Konieczny D., Jeznach O., Budnicka M., Szymaniak M.
The synthesis method of poly (glycerol succinate)
PL, Politechnika Warszawska
238248
WUP 18/2021
2021-08-02



425049
2018-03-27
BUP 21/2019
2019-10-07
Kołbuk-Konieczny D., Urbanek-Świderska O., Przybysz S., Gloc M.
Method of surface treatment and an implant produced using the surface treatment
PL, Instytut Podstawowych Problemów Techniki PAN
236812
WUP 04/2021
2021-02-22



421696
2017-05-24
BUP 25/2018
2018-12-03
Frąś L.J., Kołbuk-Konieczny D., Pręgowska A.
Measuring holder for the split Hopkinson bar and method for measuring behaviour of a material, in which the split Hopkinson bar is used
PL, Instytut Podstawowych Problemów Techniki PAN
234657
WUP 03/2020
2020-03-31



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