Construction Of Antibacterial Surface Of Medical Catheter And Its Antibacterial And Biological Properties

Bacterial attachment and the subsequent formation of biofilm on surfaces are serious problems in biomedical materials applications such as prosthetic devices,artificial gingiva,contact lenses,and catheters.Bacterial-induced catheter-related infections are the most common complications in hospitals,therefore,preventing the bacterial colonization of catheter surfaces and limiting the spread of infections are considered one of the major health challenge in healthcare units worldwide.Antibacterial coatings have been considered as an promising method for preventing the implant-associated infections caused by the bacterial colonization in virtue of the coating can impart desired surface functions via simple and efficient method without affecting bulk mechanical properties.Polyelectrolytes are widely used in the preparation of new nanomaterials,catalysts,drug delivery,controllable osmotic membranes and gene therapy due to their unique properties.One of the important applications of polyelectrolytes is to construct surface antimicrobial coatings.At present,the main problems of polyelectrolyte-based antimicrobial coating are time-consuming,low grafting density and cross-infection.Therefore,it is challenging to construct a simple and efficient antimicrobial coating on the surface of catheter.We have noticed a system in which an equimolar mixture of polyelectrolyte and opposite charged surfactant could form water-insoluble but organic solvent-soluble complexes.Therefore,based on the antimicrobial polyelectrolyte,we synthesized a series of water-insoluble but organic solvent-soluble polyelectrolyte-surfactant complexes,which can easily and efficiently form stable coatings on most biomedical materials and show good antimicrobial and biocompatibility.(1)Based on cationic polyelectrolyte?-poly-?-lysine(PL),a water-insoluble but organic solvent-soluble antimicrobial complex agent(PL-AOT)was prepared by electrostatic interaction between PL and anionic surfactant 1,4-bis(2-ethylhexyl)sulfosuccinate(AOT),PL-AOT complex was applied to the surface of catheters to construct antimicrobial coatings.The process is simple,efficient and low cost.Furthermore,it can be used to construct antimicrobial surfaces on various medical devices attributed to the formation of the coating was independent of the type and shape of the base material.Almost 100%S.aureus and E.coli as Gram-positive and Gram-negative bacteria model could be killed rapidly by this coating for thermoplastic polyurethane(TPU)film.The antibacterial properties of the coated catheters were also assessed under static and dynamic flow conditions.Regardless of the above conditions,the coated catheters displayed remarkable antibacterial activity compared to the uncoated catheters.In addition,this coating showed better antibacterial stability by mimicking the in vivo environment.The coated catheter exhibited negligible cytotoxicity against L929 murinefibroblasts cells.For in vivo experiment,the coated catheter caused 90%less inflammation in mice and showed more remarkable antibacterial performance.(2)Poly(hexamethylene biguanide)hydrochloride(PHMB),as a broad-spectrum bactericide,has better antimicrobial activity than PL.By exploring the yield and solubility of the complexes of PHMB with different anions reactant,it was found that the formation and properties of the complexes were determined by the number of charges and the length of alkyl chain.Therefore,poly(hexamethylene biguanide)hydrochloride sodium stearate complex(PHMB-SS)was selected as the coating agent for the surface of medical catheters.It is confirmed that the PHMB-SS complex was successfully synthesized by ~1H NMR and FTIR characterization.The TGA was evaluated the thermal stability of the PHMB-SS complex.The better antibacterial activity of PHMB-SS coated films was proved via colony count.The PHMB-SS coated catheters could prevent the bacterial colonization in an implant-associated bacterial infection animal model in vivo.Moreover,no significant cytotoxicity and host response were observed in vitro and in vivo,indicating the high biocompatibility of the coating.