Study On Biocompatibility Modification Of Medical Polyvinyl Chloride Extracorporeal Circulation Catheter

As a matrix material for cardiopulmonary bypass catheter,medical polyvinyl chloride(PVC)has low price and good physical,it also has some mechanical properties and a certain biological function,but the biocompatibility of medical polyvinyl chloride can't meet the needs of clinical application.In this study,the electrostatic self-assembly technique was used to assemble cationic polysaccharide chitosan and anionic anticoagulant glycosaminoglycan heparin together to form a stable polysaccharide anticoagulant coating deposited on the internal surface of the medical polyvinyl chloride extracorporeal circulation catheter,and the chitosan quaternary ammonium salt and benzalkonium chloride were separated by the coupling agent method and the swelling method respectively.Coating on the outer surface of the catheter.After the anticoagulant modification,the water contact angle on the surface of PVC was alternately changed with the change of the outer layer,which confirmed the successful assembly of the anticoagulant coating of chitosan heparin sodium.The presence of-S=O absorption peak in ATR-FTIR characterization further demonstrated that anticoagulant heparin was successfully coated on the surface of the material.The results of XPS analysis show the changes of various elements on the surface of the material,which better explain the process of coating assembly.The results of SEM showed that the surface of the modified PVC was smooth and smooth.After modification,the surface of PVC showed a molecular brush structure,which confirmed the existence of the modified coating.The surface topography of the material was observed by AFM.The results showed that the surface of the modified PVC was smooth and smooth,while the surface of the modified PVC had a certain degree of roughness.Clotting test results showed that compared with the modified materials,the APTT and PT of the coating were significantly prolonged and had better anticoagulant effect.The results of protein adsorption test showed that the surface of the modified coating decreased the adsorption of protein.In addition,ATR-FTIR,XPS and SEM showed that the surface of the PVC modified by the two methods was no longer smooth and smooth,which proved that the antibacterial coating was successfully coated on the surface of PVC.The results of bacteriostasis experiment showed that PVC modified by coupling agent could obviously inhibit the growth and propagation of gram-negative Escherichia coli,but the inhibition effect of polyvinyl chloride on Escherichia coli was not obvious.The bacteriostatic kinetics further reflected the antibacterial process of the two methods after coating modification.The above results show that the modified PVC has better biocompatibility.