Influence of Hydroxyl Groups on the Cell Viability of Polyhydroxyalkanoate (PHA) Scaffolds for Tissue Engineering

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-<i>co</i>-3-hydroxyvalerate-<i>co</i>-2,3-dihydroxybutyrate) [PHBVDB] containing hydroxyl groups was produced by recombinant <i>Ralstonia eutropha</i>. <i>R. eutropha</i> were constructed to express the propionate-coenzymeA transferase (<i>pct</i>) gene from <i>Megasphaera elsdenii</i>, and glycolate was used as the carbon source. Disruption of <i>phaA</i> encoding β-ketothiolase in the <i>phaCAB</i> 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

Oil-free hyaluronic acid matrix for serial femtosecond crystallography.

結晶を損傷しない新しいタンパク質結晶の輸送媒体を発見－タンパク質の結晶構造解析で新薬創生に一歩近づく. 京都大学プレスリリース. 2016-04-22.The grease matrix was originally introduced as a microcrystal-carrier for serial femtosecond crystallography and has been expanded to applications for various types of proteins, including membrane proteins. However, the grease-based matrix has limited application for oil-sensitive proteins. Here we introduce a grease-free, water-based hyaluronic acid matrix. Applications for proteinase K and lysozyme proteins were able to produce electron density maps at 2.3-Å resolution