Improved biocompatibility and degradation behavior of biodegradable Zn-1Mg by grafting zwitterionic phosphorylcholine chitosan (PCCs) coating on silane pre-modified surface

Abstract With the purpose of regulating corrosion behavior and improving the biocompatibility of Zn-1 Mg alloy, we developed a phosphorylcholine chitosan (PCCs) coating forming a bionic cell membrane surface, using a silane conversion layer (APTEs) as the connection layer. Atomic force microscopy (AFM), contact angle (CA), and nano-scratch tests were conducted to study the surface roughness, the hydrophilicity and the adhesion strength of the PCCs layer. Bonding details were investigated by X-ray photoelectron spectroscopy (XPS) and Fourier Transform infrared spectroscopy (FTIR). Electrochemical impedance spectroscopy (EIS) tests were performed in simulated body fluid (SBF) at 37 °C to understand the degradation behavior in vitro. The experimental results demonstrated that the PCCs coating remarkably increased resistance against corrosion attack, with approximately 2 order higher value of the film resistance (Rf) than that of the substrate. Simultaneously, the PCCs-modified surface exhibited improved blood compatibility, anti-platelet adhesion, and significantly enhanced cyto-compatibility for human vascular endothelium cells (HUVECs). These results relates to the decreased release of Zn2+ and the considerably enhanced surface hydrophilicity. PCCs coated Zn alloys presented in this work are indeed showing the promise for future application in biodegradable vascular stent.