Research Progress of Antibacterial Coating for Medical Catheter

Catheter is one of the widely used medical instruments at present, but its materials are mostly hydrophobic polymers, which have no antibacterial properties and are easy to make bacteria adhere to its surface and cause serious infection problems. Catheter-related infection (CRI), as one of the most common nosocomial infections, leads to mortality and morbidity, which greatly affects medical treatment and patients' health. Therefore, it has become a common clinical problem to avoid infection when a catheter is implanted into human body. Biofilm formed by bacterial colonization is the main cause of catheter-related infection. At present, researchers mainly prepare functional coatings on the surface of medical catheters to limit bacterial colonization and inhibit the formation of biofilms, so as to effectively avoid infection. In this paper, surface modification strategies of medical catheters in recent years were summarized, which were mainly carried out from three aspects: antifouling modification, sterilization modification and antifouling-sterilization modification. Antifouling modification was generally done by preparing hydrophilic nonionic polymers (e.g., polyethylene glycol, polyvinylpyrrolidone) and zwitterionic polymers on the material surface. The surface of the catheter material was changed from hydrophobic to hydrophilic to improve the surface lubrication performance. At the same time, it could prevent the adhesion of bacteria, proteins and other substances and inhibit the formation of biofilms, but it had no bactericidal ability. Fungicidal modification was to endow the surface with bactericidal ability by grafting or loading fungicides on the surface of the catheter. According to the mechanism of fungicides, it could be divided into killing, releasing and killing or multi-mechanism combined killing. Killing meant that the surface could kill bacteria on the surface of the catheter, but it was likely to fail under complex conditions. Common fungicides were quaternary ammonium salt, chitosan and antibacterial peptide. Release killing meant that the disinfectant released from the surface loaded with disinfectant could kill the bacteria inside and on the surface of the material, but with the release of disinfectant, it was likely to run out of disinfectant. Common release fungicides were nano-metal, antibiotics and gaseous molecule. Multi-mechanism combined killing referred to the combination of fungicides with multiple killing mechanisms, such as killing and release killing, killing and photothermal killing, etc. By combining fungicides with multiple killing mechanisms, the problems of sterilization surface failure and drug resistance of bacteria could be better avoided, and better antibacterial and anti-biofilm effects could be achieved. Antifouling-bactericidal modification mainly through the preparation of composite materials and polymer brushes and building self-adaptive surface and hydrophilic polymer loaded with fungicides made the surface have both antifouling and bactericidal capabilities in order to achieve better antibacterial and anti-bio-film performance and prolong the time of infection. On this basis, this paper summarized the research progress of medical catheter surface coating in recent years, and looked forward to its existing problems. It is hoped that more and more medical antimicrobial catheters can be used in clinic by simplifying coating preparation steps, conducting more simulated in vivo experiments and clinical experiments, and lengthening the experimental cycle, etc., so that more and more medical antimicrobial catheters can be used in clinic. © 2024 Chongqing Wujiu Periodicals Press. All rights reserved.