Influence Of Oligo Hydroxyalkanoates On The Viability Of Mouse Fibroblast Cell Line L929

The biocompatibility of the tissue engineer materials was also due to the degradation productsreleased from the polymers, besides the surface hydrophilicity, surface energy and so on. Oligohydroxyalkanoates (OHAs) are degradation products of the biopolyesters-polyhydroxyalkanoates(PHA) that have been investigated for tissue engineering application. Cellular responses toOHAs had become important in evaluation of PHA biocompatibility. In this study,oligo(3-hydroxybutyrate) (OHB, M_n 2,000), oligo(3-hydroxybutyrate-co-4-hydroxybutyrate)(O3HB4HB, M_n 2,100, 6 mol% 4HB), oligo(3-hydroxybutyrate-co-3-hydroxyhexanoate)(OHBHHx, M_n 2,800, 12 mol% 3HHx) and medium-chain-length oligo(3-hydroxyalkanoates)(mclOHAs, M_n 2,400, 2 mol% 3-hydroxyhexanoate (3HHx), 25 mol% 3-hydroxyoctanoate(3HO), 71 tool% 3-hydroxydecanoate (3HD) and 3 mol% 3-hydroxydodecanoate (3HDD) wereprepared using methanolysis. There was no detectable toxic crotonic acid formed from the~1H-NMR (nuclear magnetic resonance) spectroscopy. The T_g, T_m of the oligomers weredecreased with the increasing of the monomer chain length.MTT assay, cell apoptosis study and flow cytometry were used to evaluate cell viability ofmouse fibroblast cell L929. All four kinds of oligomers formed insoluble particles in aqueoussolution. For simulating the reaction of the cells to OHA better, leptosomes were employed toencapsulate OHAs to facilitate OHAs transfer into the cytosol. The in vitro studies demonstratedthat OHAs in concentration lower than 20 mg/L did not significantly affect cell viability, whileOHAs over 40 mg/L reduced cell viability including more cell apoptosis, more cell death,delayed cell cycle and reduced cell proliferation. The cytotoxicity of OHAs decreased withincreasing OHAs side chain length. Based on the better biocompatibility of medium chain lengthOHAs, it is proposed that medium chain length hydroxyalkanoate containing PHA, such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and medium-chain-length PHA areperferred for development and application as PHA based tissue engineering biomaterials.