Polyhydroxyalkanoates (PHAs) are biopolyesters that have been studied as tissue engineering materials because of their biodegradability, biocompatibility, and low cytotoxicity. In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-2,3-dihydroxybutyrate) [PHBVDB] containing hydroxyl groups was produced by recombinant Ralstonia eutropha. R. eutropha were constructed to express the propionate-coenzymeA transferase (pct) gene from Megasphaera elsdenii, and glycolate was used as the carbon source. Disruption of phaA encoding β-ketothiolase in the phaCAB operon increased 2,3-dihydroxybutyrate (2,3-DHBA) compositions to 3 mol %. The PHBVDB film showed a lower water contact angle compared with other PHA films, indicating increased hydrophilicity due to the hydroxyl groups. The mechanical properties of the PHBVDB scaffold met the requirements for a soft tissue matrix. The effect of hydroxyl groups on cytotoxicity was evaluated with human mesenchymal stem cells. Results of cell proliferation and live/dead assays showed that the PHBVDB scaffold did not exhibit significant cytotoxicity toward the cells. These results indicate that PBVDB containing hydroxyl groups could be applied as a hydrophilicity-controlled scaffold for soft tissue engineering.
Keywords: Ralstonia eutropha; hydroxyl group; polyhydroxyalkanoate; scaffold; tissue engineering.