Cell attachment on poly copolymer produced by Azotobacter chroococcum 7B

• Published in: BMC biochemistry 2013-05, Vol.14
• Main Authors: Bonartsev, Anton P, Yakovlev, Sergey G, Zharkova, Irina I, Boskhomdzhiev, Arasha P, Bagrov, Dmitrii V, Myshkina, Vera L, Makhina, Tatiana K, Kharitonova, Elena P, Samsonova, Olga V, Feofanov, Alexey V, Voinova, Vera V, Zernov, Anton L, Efremov, Yurii M, Bonartseva, Garina A, Shaitan, Konstantin V, Kirpichnikov, Michail P
• Format: Article
• Language: English
• Subjects: Cell adhesion; Chemical properties; Physiological aspects; Surface energy
• ISSN: 1471-2091; 1471-2091
• DOI: 10.1186/1471-2091-14-12

Background The 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). Results In 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 .sup.1H nuclear-magnetic resonance (.sup.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. Conclusions Thus, 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. Keywords: Poly(3-hydroxybutyrate), Poly(ethylene glycol), Copolymer, Hydrophilicity, Biocompatibility, COS-1