Biomimetic Mineralization Strategies to Construct Heparin/Titanium Dioxide Anticoagulant and Antimicrobial Coatings for Blood Contact Devices

Current methods for applying antithrombotic and antibacterial coatings to blood-contacting biomedical materials and devices are often intricate and costly, limiting their practical application. Inspired by biomimetic mineralization strategies, we have developed a heparin/titanium dioxide composite coating that provides exceptional lubricating, anticoagulant, and antimicrobial properties. Our method begins with the formation of a base layer on the substrate via a Schiff base reaction between dopamine and polyethylenimine, followed by the immobilization of heparin through an amide reaction. Subsequently, ammonium oxo-lactato-titanate (TiBALDH) is adsorbed onto the heparin-functionalized layer, facilitating the in situ generation of titanium dioxide through a biomimetic mineralization approach. Our findings demonstrate that this coating is stable and biocompatible, with the titanium dioxide component significantly enhancing hydrophilicity, thereby improving self-cleaning and antifouling properties. This effectively prevents the adsorption of proteins and the adhesion of microbial and blood cells. The high heparin content of the coating effectively resists thrombosis by inactivating coagulation factors. Furthermore, the combination of the polydopamine layer and heparin complex endows titanium dioxide with photocatalytic properties under visible light, enabling it to generate reactive oxygen species that effectively kill bacteria. In conclusion, the coating developed in this study is stable and exhibits self-cleaning, antifouling, antithrombotic, and antibacterial properties, coupled with excellent biocompatibility. This work offers a promising avenue for the development of blood-contacting materials in the biomedical industry.