Surface Modification of Polycarbonateurethane by Grafting Phosphorylcholine Glyceraldehydes for Improving Hemocompatibil
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Surface Modification of Polycarbonateurethane by Grafting Phosphorylcholine Glyceraldehydes for Improving Hemocompatibility Wei Gao 1, Yakai Feng 1,2, Jian Lu1 and Jintang Guo 1,2 1 School of Chemical Engineering and Technology, Tianjin University, Weijin Road 92, Tianjin, China 2 Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, Tianjin, China ABSTRACT Phosphorylcholine glyceraldehyde (PCGA) was used as a phosphorylcholine (PC) group containing compound to graft onto the surface of polycarbonateurethane (PCU) film using 1,6-hexanediamine (HDA) or α,ω-diamino-poly(ethylene glycol) (APEG, Mn = 200) as a spacer, in order to introduce biomimetic structure onto the polymer surface. X-ray photoelectron spectroscopy (XPS) analysis shows that PCGA has been covalently linked to the PCU surface. Water contact angle test suggests that the surface hydrophilicity has been improved after PCGA is grafted onto the surface of PCU film. Scanning electron microscope (SEM) observation of the modified PCU films after contacting with plasma-rich plasma demonstrates that platelets rarely adhere but a large number of platelets adhere to the original PCU surface. The hemocompatibility of the PC modified PCU film has been improved obviously after grafting with PCGA with PEG spacer. INTRODUCTION High hemocompatibility is one of the important properties required for artificial vascular grafts and other biomedical devices contacting with blood in vivo especially for a long period of time [1]. An effective way to improve the hemocompatibility of relative biomaterials is to modify the surface structure and to optimize the surface properties correspondingly [2]. Phosphorylcholine (PC) is a zwitterionic molecular segment present at the end of some lipids and on the external surface of cell membrane. Many researchers reported using PC-based compounds to improve the hemocompatibility of biomaterial surface [3]. In this study, we used phosphorylcholine glyceraldehyde (PCGA), a PC-based compound, to graft onto the surface of polycarbonateurethane (PCU) film via a three-step procedure, in order to introduce a biomimetic structure onto the polymer surface. Firstly, 1, 6-hexamethylene diisocyanate (HDI) was grafted onto the PCU film. Then, 1, 6-hexanediamine (HDA) or α,ω-diamino-poly(ethylene glycol) (APEG, Mn = 200) as a spacer was linked to PCU surface to create primary amine groups on the surface. Finally, PCGA was introduced onto PCU surface via the reductive amination reaction. The PC-modified PCU film is expected to promote its hemocompatibility due to the potential advantages including: (1) the hydrophilic zwitterionic phospholipid groups could self-assembly on the PCU film surface in an aqueous environment. The hydrophobic aliphatic chain of HDA will pull the molecular self-assembly to form a specific biomimetic surface [4, 5]; (2) a ‘‘barrier’’ created by structured water associated with the hydrophilic PEG chain can
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prevent the absorption of plasma albumen and re
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