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Streszczenie:
Biodegradable 3D-printed polycaprolactone scaffolds for bone tissue engineering applications have been extensively studied as they can provide an attractive porous architecture mimicking natural bone, with tunable physical and mechanical properties enhancing positive cellular response. The main drawbacks of polycaprolactone-based scaffolds, limiting their applications in tissue engineering are: their hydrophobic nature, low bioactivity and poor mechanical properties compared to native bone tissue. To overcome these issues, the surface of scaffolds is usually modified and covered with a ceramic layer. However, a detailed description of the adhesion forces of ceramic particles to the polymer surface of the scaffolds is still lacking. Our present work is focused on obtaining PCL-based composite scaffolds to strengthen the architecture of the final product. In this manuscript, we report qualitative and quantitative evaluation of low temperature plasma modification followed by detailed studies of the adhesion forces between chemically attached ceramic layer and the surface of polycaprolactone-nanohydroxyapatite composite 3D-printed scaffolds. The results suggest modification-dependent alteration of the internal structure and morphology, as well as mechanical and physical scaffold properties recorded with atomic force microscopy. Moreover, changes in the material surface were followed by enhanced adhesion forces binding the ceramic layer to polymer-based scaffolds.

Słowa kluczowe:
surface modification, low temperature plasma, atomic force microscopy, bone tissue engineering

Streszczenie:
Composite scaffolds of bioactive glass (SiO2-CaO) and bioresorbable polyesters: poly-L-lactic acid (PLLA) and polycaprolactone (PCL) were produced by polymer coating of porous foams. Their structure and mechanical properties were investigated in micro and nanoscale, by the means of scanning electron microscopy, PeakForce Quantitative Nanomechanical Property Mapping (PF-QNM) atomic force microscopy, micro-computed tomography and contact angle measurements. This is one of the first studies in which the nanomechanical properties (elastic modulus, adhesion) were measured and mapped simultaneously with topography imaging (PF-QNM AFM) for bioactive glass and bioactive glass – polymer coated scaffolds. Our findings show that polymer coated scaffolds had higher average roughness and lower stiffness in comparison to pure bioactive glass scaffolds. Such coating-dependent scaffold properties may promote different cells-scaffold interaction.

Słowa kluczowe:
bone tissue engineering, composite scaffold, bioactive glass, mmechanical properties

Streszczenie:
Outside the wide range of potential benefits, the use of nanomaterials can endanger human health, mostly through skin contact and the risk of inhalation. This article presents the results of harmonized measurements with contextual information on the emission of nanoparticles during the manufacturing and application of nanotechnology products. The purpose of the research was to investigate the actual levels of exposure to nano-objects in real working conditions in chosen Polish companies. Measurements were carried out in various workplaces: during silver nanoparticle synthesis, production of thin nanocarbon layers, 3D-printing with the use of a nanohydroxyapatite-polymer composite and the production of special seals from thin glass foils. Research was conducted on the basis of task-based measurements and offline microscopic analysis. Real-time particle DiSCmini counters were used to determine the nano-object concentration during different processes and events: samplers for collecting air dust, and a scanning electron microscope to confirm the presence of nanoparticles emitted from selected sources. Average particle sizes obtained with analysis of microscopic images were as follows: 46.7 ± 13.4 nm, 19.8 ± 4.8 nm, 22.4 ± 7.6 nm, 49.2 ± 26.3 nm respectively for workplaces. The concentration during significant events was referred to the background particle level. During one of the repeated processes, an unexpected and extremely high nanoparticle emission was recorded, which, in the long run, could cause a health hazard to workers. The studies have shown the importance of collective protective measures, revealed unexpected sources of accidentally generated nanoparticles and allowed to obtain knowledge about levels of exposure to nanoparticles during the various processes.

Słowa kluczowe:
nanoparticles, ultrafine particles, occupational exposure, field monitoring, occupational health, real-time measurement