| Polyurethanes (PU) are widely used in the medical devices, such as catheters, cardiac assisting devices, artificial heart, cardiovascular biomaterials, hemodialysis bloodline sets, center venous catheters (CVCs), and intravenous (IV) bags, etc, due to their excellent physic-mechanical properties and relatively good biocompatibility. However, microscopic thrombi and microemboli have been observed in some PU implants. So the hemocompatibility of polyurethanes can not meet the requirements of the clinical long-term implantation. Hence, it is of great necessity to modify the surface of PU biomedical devices and therefore enhance their hemocompatibility.In this paper, A PU membrane was obtained by a novel four step graft procedure.The CMCS was introduced by Potassium persulfate graft copolymerization in the Presence of formaldehyde as cross linking agent. AS the liquidity and hydrophilic of PEG, The formation of hydrated PEG can prevent protein and platelet adhesion. Meantime, The negative charge on the CMCS has played an electrostatic repulsion, thus demonstrated anticoagulant. This film reflects the synergistic effect of the exclusion of the PEG movement and CMCS.Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analysis confirmed that carboxyl-chitosan was grafted onto polyurethanes surface. The surface properties of unmodified and modified PU films were determined and compared by water contact angle assessment. After PEG and CMCS grafting, the surface energy of the PU film was increased. Furthermore, the hemocompatibility of the modified PU films was systematically evaluated by Bovine serum albumin (BSA) adsorption, the dynamic blood clotting test, the platelet adhesion test and the hemolytic test. It appears that BSA adsorption and platelet adhesion were significantly curtailed for the modified PU films. Therefore, the obtained results showed the modified PU film has better hemocompatibility. |
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