The Influence of the Polymer Amount on the Biological Properties of PCL/ZrO₂ Hybrid Materials Synthesized via Sol-Gel Technique.

Organic/inorganic hybrid materials are attracting considerable attention in the biomedical area. The sol-gel process provides a convenient way to produce many bioactive organic-inorganic hybrids. Among those, poly(e-caprolactone)/zirconia (PCL/ZrO₂) hybrids have proved to be bioactive with no toxic materials. The aim of this study was to investigate the effects of these materials on the cellular response as a function of the PCL content, in order to evaluate their potential use in the biomedical field. For this purpose, PCL/ZrO₂ hybrids containing 6, 12, 24, and 50 wt % of PCL were synthesized by the sol-gel method. The effects of their presence on the NIH-3T3 fibroblast cell line carrying out direct cell number counting, MTT, cell damage assays, flow cytometry-based analysis of cell-cycle progression, and immunoblotting experiments. The results confirm and extend the findings that PCL/ZrO₂ hybrids are free from toxicity. The hybrids containing 12 and 24 wt % PCL, (more than 6 and 50 wt % ones) enhance cell proliferation when compared to pure ZrO₂ by affecting cell cycle progression. The finding that the content of PCL in PCL/ZrO₂ hybrids differently supports cell proliferation suggests that PCL/ZrO₂ hybrids could be useful tools with different potential clinical applications.