Surface Characterization And Antithrombogenicity Research Of Dacron

In recent years, synthetic polymers are widely used to biomedical materials for artificial organs including cardiovascular artificial organs. However, when blood-contacting polymers meet blood, complicated interaction will happen on the interface so as to form coagulable reaction and thrombus, so the farther application of synthetic polymers in blood-contacting devices was restricted. Therefore, blood-contacting polymers need to be modified to improve their antithrombogenicity, and this has become the focused research.In this paper, the poly(ethylene terephthalate, PET) films were modified using two kinds of surface modification methods. One is gas(Ar, 02) plasma treating, ultraviolet (UV) irradiation grafting and chemical immobilizing by anticoagulant hirudin on the PET surface, which is labled chemical grafting method. The other method is immobilization of hirudin with glutaraldehyde, which is labled glutaraldehyde immobilization method. The surface hydrophilicity, surface free energy, and blood compatibility of these modified PET films were studied and the influence of processing conditions(powertreatment time gas sorts UV irradiation time hirudin concentration glutaraldehyde concentration dipped time) on these proprieties were studied as well.The surface structure and constitution of the modified PET were determined by X-ray photoelectron spectroscopy (XPS). The contact angle of PET films was measured by a contact angle geniometer. Platelet adhesion, coagulation factor experiments and denatured fibrinogen experiments were conducted to evaluate the blood compatibility of materials.XPS indicated that hirudin was immobilized on PET films successfully by two kinds of methods. Compared to virgin PET, the change of water contact angle ofchemical grafting method was not distinct. The possible reason is that 49 amino acid in the end of hirudin chain is hydrophobic groups. However, the water contact angle of hirudin immobilization with glutaraldehyde decreased evidently (from 74.1° to 57°). The possible reason is hirudin contains hydrophilic groups such as -O-, -OH, R-COO~, and these hydrophilic groups could form hydrogen bond with water molecules so as to strengthen hydrophilicity. The ratio of dispersive / polar component of the surface energy and interface energy between materials and biological substances depresses gradually with increasing of glutaraldehyde concentration. When the concentration of glutaraldehyde was 2.0% nearby, the activated PET reached to saturation, and the ratio of dispersive / polar component of the surface energy and interface energy between materials and with biological substances went calmly. The number of platelet adhesion decreased with increasing glutaraldehyde concentration. When the concentration of glutaraldehyde was 2.0% nearby, the number of adhered platelet was fewest. The ratio of dispersive / polar component of the surface energy and interface energy between materials and with biological substances was same in trend, which corresponding to the results of platelet adhesion as well on chemical grafting methods.The results of coagulant factor tests revealed that the activated partially thromboplastion time (APTT) of hirudin immobilized PET by two kinds of methods was longer than virgin PET films. The activated partially thromboplastion time (APTT) of hirudin immobilized PET by chemical grafting method was 47.2s and the virgin PET was 43.4s. The activated partially thromboplastion time (APTT) was 45 s hirudin immobilized PET by glutaraldehyde immobilization method and the virgin PET was 42.4s. The change of APTT indicated that the modified PET films could influence markedly intrinsic coagulant system. The changes of the...