Cell attachment on poly(3-hydroxybutyrate)-poly(ethylene glycol) copolymer produced by Azotobacter chroococcum 7B

Abstract

BackgroundThe improvement of biomedical properties, e.g. biocompatibility, of poly(3-hydroxyalkanoates) (PHAs) by copolymerization is a promising trend in bioengineering. We used strain Azotobacter chroococcum 7B, an effective producer of PHAs, for biosynthesis of not only poly(3-hydroxybutyrate) (PHB) and its main copolymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB-HV), but also alternative copolymer, poly(3-hydroxybutyrate)-poly(ethylene glycol) (PHB-PEG).ResultsIn biosynthesis we used sucrose as the primary carbon source and valeric acid or poly(ethylene glycol) 300 (PEG 300) as additional carbon sources. The chemical structure of PHB-PEG and PHB-HV was confirmed by 1H nuclear-magnetic resonance (1H NMR) analysis. The physico-chemical properties (molecular weight, crystallinity, hydrophilicity, surface energy) and surface morphology of films from PHB copolymers were studied. To study copolymers biocompatibility in vitro the protein adsorption and COS-1 fibroblasts growth on biopolymer films by XTT assay were analyzed. Both copolymers had changed physico-chemical properties compared to PHB homopolymer: PHB-HV and PHB-PEG had less crystallinity than PHB; PHB-HV was more hydrophobic than PHB in contrast to PHB-PEG appeared to have greater hydrophilicity than PHB; whereas the morphology of polymer films did not differ significantly. The protein adsorption to PHB-PEG was greater and more uniform than to PHB and PHB-PEG copolymer promoted better growth of COS-1 fibroblasts compared with PHB homopolymer.ConclusionsThus, despite low EG-monomers content in bacterial origin PHB-PEG copolymer, this polymer demonstrated significant improvement in biocompatibility in contrast to PHB and PHB-HV copolymers, which may be coupled with increased protein adsorption and hydrophilicity of PEG-containing copolymer.

Poly(hydroxybutyrate‐co‐hydroxyvalerate) and bovine serum albumin blend prepared by electrospinning

“…Usually, the addition of a hydrophilic component to a hydrophobic water‐insoluble polymer causes a decrease in the contact angle. This was observed, for example, for the electrospun composite made of nylon 6 and methoxy poly(ethylene glycol) oligomer, the electrospun blend poly(lactic‐co‐glycolic acid), PLGA+chitosan, and the solution‐cast PHB films with the addition of poly(ethylene glycol) (PEG) …”

Effect of Poly(ethylene glycol) on the Ultrastructure and Physicochemical Properties of the Poly(3‐hydroxybutyrate)

“…Thus, despite the low percentage of EG monomers the changes in physicochemical properties were noticed. As compared to homopolymer, copolymer PHB‐PEG has higher hydrophility parameters, as demonstrated early, it demonstrates a significant decrease in Young's modulus and elastic properties. The composite PHB + PEG obviously has better hydrophility and mechanical properties.…”

“…Polymer films were examined with SEM and AFM. We studied morphology of the smooth side of polymer films, because it was shown previously that a smooth film surface reflects the properties of the polymeric material much better than the rough side, the structure of which is highly dependent on the film preparation technique . The surface microstructures of PHB, PHB + PEG, and PHB‐PEG are presented at Figure .…”

“…The following materials were used: native poly(3‐hydroxybutyrate) (PHB) Mw = 4.85 × 105, its copolymer poly(3‐hydroxybutyrate)‐poly(ethylene glycol) (PHB‐PEG) Mw = 2.17 × 105, PEG Mw = 1500 …”

Biocompatibility of electrospun poly(3-hydroxybutyrate) and its composites scaffoldsfor tissue engineering

“…Количество живых клеток определяли по стандартной калибровочной прямой для теста ХТТ. Эти данные представлены как характеристика биосовместимости in vitro полимерных плёнок [6][7][8].…”