Poly(ethylene glycol)-modulated cellular biocompatibility of polyhydroxyalkanoate films

Polyhydroxybutyrate (PHB) and its copolymer with hydroxyvalerate, P(HB-co-HV), are widely used biomaterials. In this study,improvements of their biological properties of degradability and compatibilitywere achieved by blending with low-molecularweightpoly(ethylene glycol) (PEG106) approved for medical use. Surface morphology and chemistry are known to supportcell attachment. Attachment and proliferation of neural olfactory ensheathing cells increased by 17.0 and 32.2% for PHBand P(HB-co-HV) composite films. Cell attachment was facilitated by increases in surface hydrophilicity, water contact anglesdecreased by 26 ± 2◦ and water uptake increased by 23.3% depending upon biopolymer and PEG loading. Cells maintainedhigh viability (>95%) on the composite films with no evidence of cytotoxic effects. Assays of mitochondrial function and cellleakage showed improved cell health as a consequence of PEG loading. The PEG component was readily solubilised fromcomposite films, allowing control of degradation profiles in the cell growth medium. Promotion of biopolymer compatibilityand degradability was not at the expense of material properties, with the extension to break of the composites increasingby 5.83 ± 1.06%. Similarly, crystallinity decreased by 36%. The results show that blending of common polyhydroxyalkanoatebiomaterials with low-molecular-weight PEG can be used to promote biocompatibility and manipulate physiochemical andmaterial properties as well as degradation.