Construction And Performance Research Of Responsive Antibacterial Surface With Integrated Bacterial Resistance,Killing And Release Properties

The biofilm formed by the adhesion and subsequent proliferation of bacteria on the surface of the material will pose a huge threat to many fields such as biomedicine and industrial production.Therefore,it is of great significance to construct an antibacterial surface to resist the initial attachment of bacteria,kill the bacteria and desorb bacteria responsively to achieve surface regeneration.In this paper,two stimuli-responsive antibacterial surfaces with triple functions of"antifouling-bactericidal-release"were constructed based on stimuli-responsive polymers and two different bacterial desorption methods.And the influence of the physical and chemical properties of the surface on its antibacterial function were systematically investigated.In this paper,the surface-initiated atom transfer radical polymerization(SI-ATRP)method was used to construct a two-layer polymer brush system with the salt-responsive poly(3-(dimethyl(4-vinylbenzyl)ammonio)propylsulfonate)(poly DVBAPS)as the under layer and the hydrophilic poly(N-hydroxyethyl acrylamide)(poly HEAA)as the upper layer.At the same time,the small molecule antibacterial agent triclosan(TCS)was modified on the poly HEAA chains to form a triple-functional antibacterial surface with integrated bacterial resistance,killing and release properties.Bacterial experiments have shown that the poly(DVBAPS-b-HEAA-g-TCS)surface has a long-term antifouling property with less than 10~6cells/cm~2bacterial adhesion on the surface in three independent long-acting bacterial cycles of 120 h and 72 h against E.coli and S.aureus.With the treatment of 1 M Na Cl solution,?90%of the attached bacteria could be released because of the?3 times stretching force generated by the stretching of poly DVBAPS chains.Furthermore,the introduction of the fungicide TCS could kill more than?90%of bacteria attached on the poly(DVBAPS-b-HEAA-g-TCS)surface.In the long-term antibacterial process,the bacterial desorption performance of the materials will be weakened because of the chain extension force generated by the stimulating responsive polymers is not enough to completely desorb the"stubborn"bacteria that adhere on the polymer chain.So we further constructed a dual-stimuli responsive antibacterial surface with dual desorption method which integrated bacterial resistance,killing and release properties based on the host-guest interaction between?-cyclodextrin(?-CD)and azobenzene(Azo)simultaneously.Specificly,we use the hydrophilic copolymer brush copolymerized by hydroxyethyl methacrylate(HEMA)and glycidyl methacrylate(GMA)modified with aminated?-CD as the host part,the copolymer P(NIPAM-AAAB)copolymerized by alkenylated azobenzene(AAAB)and N-isopropylacrylamide as the guest part,and deposit silver nanoparticles(Ag NPs)in situ to impart the surface with bactericidal properties.Bacterial experiments have shown that the P(HEMA-GMA)-?-CD/P(NIPAM AAAB)@Ag surface has a long-term antifouling property with less than 10~6 cells/cm~2 bacterial adhesion on the surface in three independent long-acting bacterial cycles of 72 h and 48 h against E.coli and S.aureus.More importantly,the releasing ratio of the attached bacteria increased from?82%to?92%after using 4°C PBS solution and 365 nm ultraviolet light in turn,and it was stable in all three cycles.At the same time,due to the presence of Ag NPs,?92%of the attached bacteria were killed by contacting.The prepared P(HEMA-GMA)-?-CD/P(NIPAM-AAAB)@Ag has excellent antifouling,sterilization and dual-stimulus responsive release properties of light and temperature.