Biosynthesis, characterisation and biocompatibility of a unique and elastomeric medium chain-length polyhydroxyalkanoates for kidney glomerular tissue engineering.

Polyhydroxyalkanoates (PHAs) are bacteria-derived polymers that are being actively explored for their potential in biomedical engineering applications. These polymers are not only highly biocompatible in nature but also sustainable, produced using renewable substrates, and hence considered future biomaterials. In addition to normal fermentation, PHAs can also be produced through a synthetic biology approach. This study explores a medium chain-length PHA (mcl-PHA) produced by CH50 by batch fermentation, fed with glucose as the sole carbon source. The polymer was extensively characterised, and it exhibited an elastomeric property of a typical mcl-PHA with 215 ± 52 % elongation at break. The mcl-PHA also had a low melting point, , of around 55 °C, making it processable with various fabrication methods. The extracted mcl-PHA was prepared as a solvent-cast film and tested as a potential cell culture substrate for human glomerular cells, the conditionally immortalised human podocytes (CiHP) and conditionally immortalised human glomerular endothelial cells (CiGEnC). Initial resazurin assay under proliferative conditions showed promising cell metabolic activities of the cells cultured on the mcl-PHA film, comparable with those cultured on tissue culture plastic (TCP). Despite the decreased expression of collagen IV under proliferative conditions, the differentiated co-cultured cells on mcl-PHA had comparable values with cells those grown on TCP. These promising results verified the biocompatibility of the mcl-PHA produced by CH50 and established its potential as a bio-based sustainable alternative in biomedical applications including glomerular tissue engineering.