In this study, sol-gel bioactive glasses and β-TCP composites were investigated regarding their thermal behaviour, microstructure, and phase composition. Sol-gel bioactive glasses based on the CaO-SiO2 -P2O5 system of either a high SiO2 content (S2) or a high CaO content (A2) were mixed with the β-TCP at 25:75, 50:50 and 75:25 weight ratios. Basing on the HSM results, i.e. shrinkage curves, densification intervals and characteristic temperatures, the sintering temperatures of composites were indicated. Scanning electron microscopy and X-ray diffraction were used to determine the microstructure and phase composition of composites after sintering at selected temperatures, i.e. 1100°C and 1200°C. The SEM/EDX investigations proved the well-sintered and densified microstructure of the sintered composites. The chemistry of sol-gel bioactive glasses influenced both the thermal beha-viour and the phase composition of the composites. The dominant phases for A2-β-TCP materials were α-TCP, pseudowollastonite and β-TCP, while for S2-β-TCP – cristobalite, β-TCP, and α-TCP. However, the content of each phase varied, depending on the A2 or S2 content in the composite composition. Hot-stage microscopy provides useful information for selecting optimal sintering temperature in order to obtain well-sintered and strengthened material. Moreover, by a carefully selected combination of sol-gel bioactive glasses and β-TCP it is possible to obtain the materials with favorable phase composition with regard to biological activity.
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.
Ceramika jest materiałem implantacyjnym powszechnie stosowanym w ortopedii oraz stomatologii. W ostatnich latach szczególną uwagę zwrócono na wykorzystanie materiałów bioaktywnych, do których należą między innymi bioaktywne szkła i szkło-ceramika. W obszarze kontaktu mają one zdolność wywołania specyficznej odpowiedzi biologicznej, która prowadzi do tworzenia trwałego wiązania pomiędzy tkanką i materiałem. Bioaktywność szkieł w dużej mierze zależy od ich składu chemicznego, procesu wytwarzania (proces wysokotemperaturowy lub zol-żel) oraz obróbki termicznej. Uwalniane z powierzchni szkła jony mogą wpływać na odpowiedź wewnątrz- i zewnątrzkomórkową. Jednoczesne aktywowanie odpowiednich genów osteoblastów prowadzi do ich proliferacji oraz produkcji macierzy zewnątrzkomórkowej. W opracowaniu przedstawiono podział ceramiki ze względu na sposób oddziaływania z tkankami, opisano mechanizm bioaktywności szkieł w kontakcie z płynem fizjologicznym, a także możliwości badania tego zjawiska w warunkach in vitro. Ponadto, dokonano porównania właściwości bioaktywnych szkieł wytwarzanych tradycyjną metodą topienia oraz metodą zol-żel.
EN
Ceramic materials are widely used in a variety of orthopaedic and dental applications. Over the last few years considerable attention has been directed towards the use of bioactive materials i.e. bioactive glasses and glass-ceramics. They have the ability to elicit a specific biological response at the interface of the material, which results in the formation of a bond between the tissues and the material. Bioactivity of glass mainly depends on the chemical composition, manufacturing process (melt and sol-gel derived glasses) and thermal treatment. The ions released from the glass surface can induce extracellular and intracellular response. Simultaneous activation of the numerous genes leads to proliferation of osteoblasts and expression of extracellular matrix components. The classification of ceramic materials based on the type of material-tissue interaction, the mechanism of glass bioactivity in physiological media, and the possibility of investigation of this phenomenon were presented. Furthermore, the properties comparison of melt-derived glasses and sol-gel-derived glasses was carried out.
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