Author(s)

Miroslav Hnatko, Zoltán Lenčéš, Peter Čopan, Lucia Birošová, Patrik Matejov, Soňa Jantová

Department of Ceramic, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia.
Institute of Biochemistry, Nutrition and Health Protection, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia.
Institute of Inorganic Chemistry, Technology and Materials, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia.

Porous Si₃N₄-SiO₂-based ceramics with different porosity were prepared via free sintering of Si₃N₄ on air with an addition of semolina (5, 10 and 20 wt%) as a pore-forming agent. The semolina content in the starting powder controlled the volume fraction of pores in the sintered body. Small pores (<5 μm) formed a continuous network in the whole volume of the ceramic material, while the large pores (~100 μm), formed from the added semolina were mostly isolated in the ceramic matrix. Mercury porosimetry and strength measurements have shown that specific surface area, volume density and compressive strength decreased with the amount of semolina in the samples. Mechanical properties similar to bone were obtained for the sample with 20 wt% semolina pore forming agent (compressive strength 350 MPa, density 2.17 g.cm^-3). The prepared Si₃N₄-SiO₂-based ceramics were evaluated for cytotoxic and genotoxic potential on human fibroblast VH10 and B-HNF-1 cells. Biological tests have shown that both these human fibroblast cell lines were sensitive to the samples with lower porosity and cell growth inhibition was observed in the range 14.9% - 21.3%. The cytotoxicity of the sample with the highest porosity (~40%) was not significant (<10%). The microscopic observations have shown that VH10 and B-HNF-1 cells growing around the silicon nitride ceramic discs were homogeneously distributed on the cultivation surface. No significant morphologic changes were found in treated cells, their morphology was very similar to that of the control cells. None of the tested Si₃N₄-based ceramic samples induced necrotic/apoptotic death of human fibroblasts. Sample S-20 had similar properties to bones and was characterized by very good biocompatibility, slight cytotoxicity and none genotoxicity. Therefore, Si₃N₄-SiO₂-based ceramics prepared by free sintering on air are potential biomaterials for medical applications.

Silicon Nitride; Sintering; Porosity; Mechanical Properties; Cytotoxicity/Genotoxicity; Human Cell Lines

M. Hnatko, Z. Lenčéš, P. Čopan, L. Birošová, P. Matejov and S. Jantová, "Synthesis, Characterizations and in Vitro Assessment of the Cytotoxicity and Genotoxicity of Novel Silicon Nitride-Based Porous Ceramics," Materials Sciences and Applications, Vol. 4 No. 7, 2013, pp. 407-418. doi: 10.4236/msa.2013.47050.