title: Cell attachment on poly(3-hydroxybutyrate)-poly(ethylene glycol) copolymer produced by Azotobacter chroococcum 7B.
abstract: 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 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.
  
  
  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.
authors.affiliation: Faculty of Biology, MV Lomonosov Moscow State University, Moscow, Russia. ant_bonar@mail.ru
authors.forename: Anton P
authors.initials: AP
authors.lastname: Bonartsev
authors.forename: Sergey G
authors.initials: SG
authors.lastname: Yakovlev
authors.forename: Irina I
authors.initials: II
authors.lastname: Zharkova
authors.forename: Arasha P
authors.initials: AP
authors.lastname: Boskhomdzhiev
authors.forename: Dmitrii V
authors.initials: DV
authors.lastname: Bagrov
authors.forename: Vera L
authors.initials: VL
authors.lastname: Myshkina
authors.forename: Tatiana K
authors.initials: TK
authors.lastname: Makhina
authors.forename: Elena P
authors.initials: EP
authors.lastname: Kharitonova
authors.forename: Olga V
authors.initials: OV
authors.lastname: Samsonova
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Feofanov
authors.forename: Vera V
authors.initials: VV
authors.lastname: Voinova
authors.forename: Anton L
authors.initials: AL
authors.lastname: Zernov
authors.forename: Yurii M
authors.initials: YM
authors.lastname: Efremov
authors.forename: Garina A
authors.initials: GA
authors.lastname: Bonartseva
authors.forename: Konstantin V
authors.initials: KV
authors.lastname: Shaitan
authors.forename: Michail P
authors.initials: MP
authors.lastname: Kirpichnikov
mesh_terms: D000327:Adsorption; D000818:Animals; D001395:Azotobacter / Q000378:metabolism*; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism; D057005:Bioengineering; D018533:Biomass; D019556:COS Cells; D002152:Calorimetry, Differential Scanning; D002522:Chlorocebus aethiops; D057927:Hydrophobic and Hydrophilic Interactions; D006885:Hydroxybutyrates / Q000737:chemistry / Q000378:metabolism; D018625:Microscopy, Atomic Force; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D014631:Valerates / Q000737:chemistry / Q000378:metabolism; D014867:Water / Q000737:chemistry; D000094122:Polyhydroxybutyrates
chemical_list: D001672:Biocompatible Materials; D006885:Hydroxybutyrates; D011091:Polyesters; D011092:Polyethylene Glycols; D011108:Polymers; D011506:Proteins; D014631:Valerates; D014867:Water; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C073314:poly(3-hydroxyvalerate)