In vitro Blood Compatibility of Polyethylene Terephthalate with Covalently Bounded Hirudin on Surface

Polyethylene terephthalate （PET,Dacron） was modified by surface immobilization of hirudin with glutaraldehyde（GA） as coupling reagent to improve the blood compatibility.Hirudin-immobilized PETs were characterized by X-ray photoelectron spectroscopy （XPS） and contact angle measurements.The blood compatibility of the PETs was evaluated by platelet adhesion evaluation and fibrinogen conformational change measurements in vitro.The results showed the decrease of platelet adhesion and activation on hirudin-immobilized PET with increasing of glutaraldehyde concentration.Fibrinogen experiment showed that fibrinogen adherence and conformational changes of PET-HRD were less than those of untreated PET,which made the materials difficult to form thrombus.The proper reason of blood compatibility improvement was low interface tension between hirudin-immobilized PETs and blood,as well as blood proteins,and low ratio of dispersive/polar component of the surface energy（γsd/γsp） and high hydrophilicity.