Synthesis of a zwitterionic silane and its application in the surface modification of silicon-based material surfaces for improved hemocompatibility.

A phosphorylcholine-like silane coupling agent bearing zwitterionic molecular structure was synthesized and studied. The chemical structure of this silane coupling agent was characterized by FTIR, 1H NMR and 31P NMR. The zwitterionic structure was successfully constructed onto the surface of silicon as a self-assembled layer (SAL). Static water contact angle, and atomic force microscopy (AFM) were used to investigate the wettability and surface topography of the modified silicon surfaces. Static water contact angle results indicated that the hydrophilicity of the surfaces could be effectively improved by the modification with this zwitterionic silane coupling agent. The changes of the topography and water contact angle of the modified surfaces with different incubation periods in PBS solution were also measured to evaluate the stability of the SALs. Blood compatibility of the modified surfaces were evaluated by testing the full-blood activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT), as well as by observing the adhered blood platelets onto the surface. The modified surfaces showed prolonged clotting time and fewer adherent platelets, revealing that the blood compatibility was evidently improved by the modification using this zwitterionic silane.