Biological activities from polyurethanes (PUs) synthesized from polyols (derived from castor oil) and isophorone diisocyanate were evaluated. In vitro degradability was evaluated by phosphate buffered saline (PBS) and antibacterial degradation with Escherichia coli and Pseudomonas aeruginosa. The biocompatibility was analyzed by: i) the antimicrobial activity against E. coli, S. aureus and P. aeruginosa, and ii) in vitro cytotoxicity assays using mouse embryonic fibroblast cell line L-929 in direct contact with the PUs and with NIH/3T3 cells in indirect contact with the PUs degradation products. PUs with polyol P1 (2,64% molar relation of pentaerythritol and castor oil) was the material with better biodegradation properties: 1.125±0.110% in 72 h by PBS at 100 ºC. In general, all materials were degraded up to 1.000±0.223% and 2.251±0.010% in 72 h by E. coli and P. aeruginosa, respectively. On the other hand, it was determined a close relationship between functionality of polyol and bacterial inhibition. The antibacterial effect of the PUs decreased by 67% for E. coli, 55% for S. aureus and 56% for P. aeruginosa after 24 h. Chemical modification of castor oil did not generate a cytotoxic effect on the tested cell lines. The evaluated materials are suggested as candidates to obtain biomaterials due to their mechanical properties and biocompatibility presented in untransformed cells.
Keywords:
castor oil; polycaprolactone; cytotoxicity; degradability; biomedical applications
