Preparation and Properties of Antibacterial Coating with Redox-responsive Drug Releasing Function Based on Macromolecule Self-assembly Colloidal Particle

Bacterial infection and the question (such as inflammation, fever and pain) caused by bacterial infection on the surface of implant metal material have become a major concern. In this study, by ultilizing electrodeposition, a colloidal particles based antibacterial coating with redox-responsive drug releasing property was prepared aiming at improving the adhesion of bacteria and subsequent formation of biofilms onto implant surfaces. Firstly, redox-responsive amphiphilic random copolymer poly-1-bromododecylmethylethylenediethacrylate quaternary ammonium salt-co-N- [2- (pyridine-2-disulfonyyl)-ethyl]-acrylamide-co-methyl acrylate (PPDM) was synthesized by a conventional free radical polymerization using bactericidal moiety 1-bromododecylmethyldimethylethyl quaternary ammonium salt (DMAC(12)), redox-responsive moiety N-[2-(pyridine-2-disulfonyyl)-ethyl]-acrylamide (PDSA) , and methyl methacrylate ( MMA ) as monomers. Proton nuclear magnetic resonance spectrometer (H-1 NMR) , Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography(GPC) were used to confirm the synthesis of PPDM. Then, the resultant copolymer and drug paracetamol(PCTM) were self-assembled together into PCTM-loaded colloidal particles (CPs). The size, morphology and drug-loading efficiency of CPs were characterized by zeta potential and nanoparticle size analyzer, transmission electron microscope (TEM) and UV irradiation. Finally, the PCTM-loaded PPDM coating was prepared on the surface of 316L stainless steel via electrodeposition using PCTM-loaded CPs as building blocks. The chemical composition, morphology and phase of the obtained coating were analyzed using ATR-FTIR, X-ray diffractometer(XRD) and scanning electron microscope (SEM). The results demonstrated that due to the existence of bactericidal cations , PCTM-loaded PPDM coating showed excellent bactericidal function against both Gram negative bacteria E. coli and Gram positive bacteria S. aureus. Moreover, the trigger release of PCTM in coating materials could be realized when glutathione (GSH) existed. When the concentration of GSH was 10 mmol/L, the amount of released PCTM was about 0. 9 mg which is three times more than that of released without GSH. Considering the antibacterial and redox-responsive drug releasing property, the PCTM-loaded PPDM coating has a great potential application onto the surface of impalnt metal. Furthermore, the entire strategy may be used in other implantations to creat functional coating to improve the bacterial infection.