Moisture-cured silicone-urethanes-Candidate materials for tissue engineering: A biocompatibility study in vitro

This study was performed to verify the response of human bone-derived cells (HBDCs) to moisture-cured silicone-urethanes (mcSUUs) in vitro, as the first step toward using them as scaffolds for bone tissue engineering. Good surgical handling, tissue cavity filling, stable mechanical properties, and potentially improved oxygen supply to cells after implantation justify the investigation of these nondegradable elastomers. A set of various mcSUUs were obtained by moisture-curing NCO-terminated prepolymers, synthesized from oligomeric siloxane diols of two different oligosiloxane chain lengths, and two different diisocyanates (MDI and IPDI), using two different NCO/OH molar ratios. Dibutyltindilaurate (DBTL) or N-dimethylethanolamine (N-met) served as catalysts. After 7 days of culture, cell number, viability, and alkaline phosphatase (ALP) activity were determined, and after 21 days, cell viability and collagen production were determined. Material characteristics significantly influenced the cell response. The mcSUUs prepared with DBTL, (widely used in the syntheses of biomaterials) were cytotoxic. The MDI-based mcSUUs were significantly more favored by HBDCs than the IPDI-based ones in all performed tests. MDI-based material with low 2/1 NCO/OH and short chain length was the best support for cells, comparable with tissue-culture polystyrene (with ALP activity even higher). HBDCs cultured on porous scaffolds from this mcSUU produced a tissue-like structure in culture. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res 94A: 71-83, 2010