A Study On The Cytocompatability Of KQAGDV Polypeptide Biomimetic Modified Polyhydroxyalkanoate

In the past decades, the family of polyhydroxyalkanoates (PHAs) has drawn a large volume of attention and been widely studied. PHAs are synthesized by microorganisms, with the character of biodegradability, biocompatibility and adjustable mechanical property, thus it is considered as a new generation of scaffold material in the field of regenerative medicine. There are several types of proteins found to attach to the surface of PHAs granules in vivo, such as repressor protein (PhaR). KQAGDV (Lys-Gln-Ala-Gly-Asp-Val) polypeptide, which can promote cell adhesion, is the specific ligand to the integrin on the cell surface. In this research, PhaR-KQAGDV protein is successfully expressed and purification. Then it is used to modify the surface of PHAs, in order to enhance the cytocompatability, and broaden the application of PHAs.In this research, PhaR-KQAGDV is tested for its ability to promote the cytocompatability of PHAs, and non-coated, PhaR coated PHAs films are used as control groups. Fluorescence microscope is applicated to observe the binding efficiency of PhaR-EGFP on different films. The intensity of green fluorescence shows PhaR binding well on the surface of PHAs. Water contact angle measurement indicates hydrophilicity of PHAs surfaces improved significantly after PhaR-KQAGDV modification. Equivalent human vascular smooth muscle cells (HuSMCs) are grown on test films. After incubating for 4 hours and 72 hours, CCK-8 trial is done to evaluate the metabolic activity, to represent cell adhesion and cell proliferation of HuSMCs. Meanwhile, laser scanning confocal microscope and scanning electron microscopy are used to confirm the results. Results show that cell adhesion and proliferation are better on KQAGDV modified surfaces than non-modified. It is concluded that the application of PhaR-KQAGDV polypeptide modifying surface of PHAs material can enhance their cytocompatability.