Construction And Medical Performance Of Environmentally Friendly Antibacterial Coatings

Antibiotic overuse can cause environmental degradation and drug resistance,posing a major danger to ecological balance and human health.Antibiotics are heavily used in the treatment of hospital infections,particularly catheter related bacterial infections.Antibiotics with limited bioavailability and inhumane handling of medical devices might cause antibiotics or drug-resistant microorganisms to enter the environment via water and soil,resulting in pollution.As a result,pursuing research into environmentally friendly anti-infective medical catheters has both scientific and practical relevance.Researchers have been working for many years to discover answers to medical catheter-related infections.Swelling impregnation,surface grafting,polyphenol modification,and layer-by-layer self-assembly are now the most used methods to develop anti-infective surfaces for medical catheters.However,all of these techniques have limitations,such as complex processes,time-consuming construction,dependence on substrates,or deeper coating colours,which limit their practical engineering usage.As a result,it is difficult to develop a highly effective anti-infective medical catheter surface in a simple and efficient approach,as well as to provide a universal and adaptable design strategy for future industrial production.Focusing on the polyelectrolyte-surfactant complex system with rich solution behavior and solid phase structure,this paper selected and designed functional polyelectrolytes.By regulating the self-assembly process of the complex,the obtained alcohol-soluble complex realized the construction of antibacterial coating on the surface of medical catheter.The construction process,which is simple,efficient,and not limited by the types and shapes of substrate materials,provides a new approach for the surface construction of multifunctional anti-infective medical devices.In addition,the advantages of low cost and being able to be used for large-scale production make the engineering application of this type of anti infection coating strategy possible.The specific content is as follows:Part one:Preparation and performance of antibacterial Poly(sodium-pstyrenesulfonate)complex coating(1)Based on the advantage that quaternary ammonium salt antibacterial surfactant seldom induce bacterial resistance,the polyelectrolyte-surfactant complex was selfassembled with Poly(sodium-p-styrenesulfonate)(PSS)through electrostatic and hydrophobic interaction.By changing the alkyl chain length of the surfactant to control the hydrophobicity of the complex,the alcohol-soluble PSS complex was further prepared.Through the solution turbidity and Isothermal Titration Calorimetry(ITC)thermodynamic characterization,it is proved that the complex process is driven by electrostatic force and hydrophobic interaction.The longer the alkyl chain of the surfactant.the stronger the hydrophobic force between the surfactant and the associated surfactant molecules on the PSS.Therefore,the binding strength between cetyltrimethylammonium bromide(C16)and PSS is the strongest.Thanks to the hydrophobic interaction or van der Waals forces between the substrate and the complex in organic solution,a simple and efficient one-step construction of the antibacterial coating was realized.It overcomes the limitations of traditional construction strategies such as time consuming,complexity and dependence on the type and shape of the substrate material.The coating exhibits antibacterial properties by releasing C16.By adjusting the concentration of coating agent,the catheter with antibacterial property and good biocompatibility can be obtained.Part two:Preparation and performance of stable and antibacterial chondroitin sulfate complex coatingPSS composites can easily and efficiently construct antibacterial coatings on the surface of catheters in one step,meeting the application needs of short-term implant medical devices.In order to further improve the stability of the coating in the complex processing environment,sterilization process and patients’ internal environment,and realize the long-term application of implant medical devices,a more stable antibacterial polyelectrolyte complex coating was further designed and applied to urinary medical devices.The multifunctional complex(CS/Si-N+)was formed via one step selfassembly synthesis of natural encrustation inhibitor chondroitin sulfate(CS)and broadspectrum bactericide organosilicon quaternary ammonium surfactant(Si-N+).The existence of covalent interaction for complex itself and interface ensured the formation of robust coating especially in harsh environments(high concentration salt solution,organic reagents,etc.).Meanwhile,benefiting from adaptive dissociation of the ion pairs in the CS/Si-N+ coating under urine electrolytes,the exposed ion groups and enhanced hydrophilicity were more conducive to the inhibition of bacterial infection and multiple encrustations simultaneously.The coating has a bactericidal rate of over 97%against multiple bacteria in antibacterial experiments in vitro.Compared with traditional antibiotic impregnated ureteral stents,the metabolic encrustation formed on the surface of CS/Si-N+ coated stents were significantly reduced by 90%.Even in simulated urine flow environments,coated ureteral stents can effectively prevent the formation of encrustation for up to 21 days due to their good stability,antibacterial properties,and surface adaptive dissociation characteristics.Also,this non-leachable and all-in-one coating shows good biocompatibility in a pig in vivo model.Such coating strategy is expected to be a practicable approach to prevent the urological medical devices related complications.Part three:Preparation and performance of stable,antibacterial and anti-adhesion polyelectrolyte copolymer complex coatingOrganic silicon quaternary ammonium salt surfactants improve the stability of complex coating and greatly extend the service life of medical device.However,it is difficult for this coating to handle issues such as bacteria,proteins,blood cells,etc.adhering to the surface of the catheter and causing thrombosis.Therefore,the complex in this part was rapidly assembled in one step between organosilicon quaternary ammonium surfactant(N+Si)and adjustable polyelectrolyte copolymer with crosslinkable,anti-adhesive and anionic groups(PSHV).A general and easy to expand method was adopted to design a polyelectrolyte complex medical catheter coating with antibacterial,anti-adhesion and stability.The regulated complex coating with nonleaching mode could be stable in harsh conditions because of cross-linked structure,while improving the biocompatibility and reducing the adhesion of bacteria,proteins and blood cells.The coated catheter exhibited good anti-bacterial infection in vitro and in vivo,owing to the synergistic effect of N+Si and zwitterionic groups.Therefore,the rationally designed complex supplied a facile coating approach for the potential development in combating against multiple complications of medical catheter.