Improved Growth Behaviors Of Fibroblasts L929 And NIH/3T3 On Biopolyesters Coated With Polyhydroxyalkanoate Granule Binding Protein PhaP Fused With Cell Adhesion Motif RGD

Polyhydroxyalkanoates (PHAs), a family of biopolyesters, have been studied as tissue engineering biomaterials due to their adjustable mechanical properties, biodegradability and tissue compatibility. Amphiphilic PHA granule binding protein PhaP has been shown to be able to bind to hydrophobic surfaces of polymers, especially PHA, via strong hydrophobic interaction. Genes of phaP and Arg-Gly-Asp (RGD) peptides, which are a cell adhesion motif recognized by many cell surface receptors, were successfully expressed and obtained as a pure fusion protein PhaP-RGD in Escherichia coli BL21 (DE3). When films of poly(3-hydroxybutyrate-co- 3-hydroxy-hexanoate) (PHBHHx), poly(3-hydroxybutyrate-co-3 -hydroxyvalerate) (PHBV) and polylactic acid (PLA) were coated with PhaP-RGD, their surface hydrophilicities all increased compared with their corresponding naked (non-coated) films, respectively. Among the three biopolyesters, PHBHHx were demonstrated to have the strongest affinity to PhaP. In vitro study showed that mouse fibroblasts L929 and mouse embryonic fibroblasts NIH/3T3 attached better and grew faster on all three PhaP-RGD coated films compared with those on PhaP coated and non-coated films, respectively. Both fibroblasts attached and grew very well on PhaP-RGD coated PHBHHx, PHBV and PLA, even in serum-free medium, while the non-coated and PhaP coated biopolyesters poorly supported the cell growth in serum free medium. These results indicate that PhaP-RGD could be used as a coating material to improve cell growth on hydrophobic biopolyesters for scaffold implant.