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Streszczenie:
Plasmonic materials have great potential to enable practical applications in the mid-infrared range and would gain in controllability if they were anisotropic. Here, we report an anisotropic mid-infrared plasmonic metamaterial made of less lossy ZnO:Al (AZO) layers embedded in a dielectric ZnWO4 matrix. The described material exhibits a resonance at the 3-4 μm region, which can be switched on/off by changing light polarisation. Polarisation-dependent reflectance spectroscopy, effective medium and finite-difference time-domain modelling demonstrate that the metamaterial exhibits an epsilon-near-zero (ENZ) hybrid photonic-plasmonic resonance, resembling radiative Berreman modes supported by bulk plasmon polaritons in metal thin films. Remarkably, electric field injection into such layers is realised in a simple far-field experiment without prism or focused beams. Importantly, the material is made with the eutectic solidification, which enables achieving AZO layers through self-organisation process. Additionally, the widely used crystal growth techniques could enable manufacturing metamaterials on a large scale using the eutectic solidification both in the bulk and thin film form. The methodology can be extended to multiple material combination and it opens the way to tuneable infrared metamaterials operating at different wavelengths that can find application such as resonant dichroic filters, reflectors, light-trapping structures, and sensors.

Streszczenie:
Sodium aluminophosphate glasses were evaluated for their bone repair ability. The glasses belonging to the system 45Na2O–xAl2O3-(55-x)P2O5, with x = (3, 5, 7, 10 mol%) were prepared by a melt-quenching method. We assessed the effect of Al2O3 content on the properties of Na2O–Al2O3–P2O5 (NAP) glasses, which were characterized by density measurements, DSC analyses, solubility, bioactivity in simulated body fluid and cytocompatibility with MG-63 cells. To the best of our knowledge, this is the first investigation of calcium-free Na2O–Al2O3–P2O5 system glasses as bioactive materials for bone tissue engineering.

Słowa kluczowe:
alumina, bioactive glass, bone tissue engineering, calcium-free bioactive glass, phosphate glass, sodium aluminophosphate glass

Streszczenie:
Two types of phosphate glasses 50Na2O-20B2O3-30P2O5 (NBP) and 30CaO-20Na2O-50P2O5 (CNP) with different content of TiO2 (0, 3 and 5 mol%) have been prepared by melt-quenching process. TiO2 was added to increase glass network stability. Physical properties of glasses were investigated by density measurements, differential scanning calorimetry and degradation in phosphate buffered saline (PBS). Biological performance of glasses in a direct contact with osteoblast-like MG-63 cells was analysed with the use of resazurin test and live-dead staining. The results show that TiO2 addition increased density, glass transition temperature (Tg) and melting temperature (Tm) of both types of glasses. In the case of NBP glasses presence of TiO2 resulted in their fast degradation in PBS and acidification of cell culture medium. As a consequence such glasses did not support cell adhesion and growth, but they can be considered for e.g. drug delivery systems. On the other hand addition of TiO2 to CNP glasses resulted in enhanced cell adhesion and viability. Particularly positive results were found for CNP glass containing 5% TiO2, so it can be a good candidate as a scaffold material for bone tissue engineering.

Słowa kluczowe:
phosphate glasses, bioactive glasses, titanium dioxide, tissue engineering