Construction And Properties Of Antibacterial And Anticoagulant Coatings For Medical Catheters

In clinical treatment practice,the high morbidity and mortality of catheter-related infection or thrombosis during implantation / intervention is a threat that cannot be ignored.As such,there is an urgent need for antibacterial and anticoagulant functionalized catheter surfaces with superior biocompatibility to reduce the incidence of catheter-related complications.In this thesis,medical polyvinyl chloride(PVC)and thermoplastic polyurethane(TPU)were endowed with antibacterial and anticoagulant functions by constructing surface coatings.Follows are the main research contents and results:1.The PVC surface was activated by one-step co-deposition of tannic acid and lysine,and then the antibacterial coating was successfully constructed on PVC surface by an amide reaction between the carboxyl group of lysine on the surface and the amino group of polylysine.The bactericidal efficiency of the antibacterial coating could reach 97.9% in static environment,and it still kept up to 86.0% after 48 hours in fluid environment,and the bacterial adhesion of the antibacterial coating decreased about 78.8% compared with pristine PVC.The biocompatibility test in vitro showed that the coated material could meet medical safety requirements.2.The TPU surface was activated by one-step co-deposition of tannic acid and lysine.Based on the long-term stability of the activated layer and the amine active sites of lysine on the surface,the anticoagulant coating was successfully constructed by an amide reaction introducing heparin.X-ray photoelectron spectroscopy and surface Zeta potential tests confirmed the successful immobilization of heparin.Water contact angle tests showed that heparinized surface had stable and long-lasting hydrophilicity.Hemolysis and cytotoxicity tests confirmed that the coating exhibited good biocompatibility.The excellent anticoagulant and antithrombotic properties of the coating were confirmed by anticoagulant measurements in vitro and a blood circulation model in vivo.3.Sodium alginate sulfate,a plant-based anticoagulant,was synthesized and covalently immobilized on the surface of TPU activated by polyphenol-amine through an amide reaction.The results of coagulation test demonstrated that sodium alginate sulfate showed better anticoagulant performance than heparin sodium at low concentrations with the increase of the degree of substitution.After surface modification,the material significantly reduced protein adsorption and inhibited platelet activation.Combined with its excellent biocompatibility,the feasibility of surface modification with sodium alginate sulfate as the heparin substitute was verified.This study developed a simple and efficient surface activation strategy.Surface activation was achieved by one-step co-deposition of tannic acid and lysine,and then antibacterial and anticoagulant functionalized coatings were successfully constructed,providing a new idea and method for surface functionalization of medical catheter materials.