Construction Of Glycopolymer-based Multi-functional Antibacterial Surfaces

Polysaccharide,as one of the most commonly existed biomolecule,plays an important role in various biological processes,such as cell-cell signaling,bacterial infection,etc.Glycopolymers,which are analogues of natural polysaccharide,feature carbohydrates as pendent and/or terminal groups.Glycopolymers could dramatically increase the affinity between carbohydrates and biomolecules.These functions of glycopolymers show great significance for the understanding and simulation of biological processes.Besides,glycopolymers are promising in many fields including drug delivery,therapeutics,biological sensing,etc.This article majors in the design of multi-functional antibacterial surfaces based upon glycopolymers.Firstly,several kinds of glycopolymers are synthesized to prepare nanocomplexes and antibacterial surfaces,which can realize the specific killing effect against Escherichia coli.Secondly,polysaccharide is chosen to be the substrate,and its derivative is synthesized and conjugate onto the substrate further.These topics aim at exploring the effects of substrates,polymer structure and modification routes on the antibacterial activity.The topics are as follows:1,Poly(2-(methacrylamido)glucopyranose)(p MAG)and poly(2-(methacryloyloxy)ethyl trimethylammonium iodide)(p METAI)are synthesized through RAFT polymerization,and the terminal group is then reduced to thiol group.After this,the polymers were mixed at different ratios and immobilized onto the surface of gold nanoparticles through Au-S bond.Finally,one kind of nanocomposite ESKAP is formed,the nanocomposite can specifically bind and kill the Escherichia coli,and the binding process could be inhibited by mannose through the competitive adhesion mechanism.The results show that the nanocomposite could effectively kill the Escherichia coli within three cycles.Besides,the nanocomposite shows good biocompatibility to the L929 cells.2,Gold nanoparticle layer(GNPL)is prepared as the substrate firstly,and 2-(methacrylamido)glucopyranose(MAG)and 2-(methacrylamido)galactopyranose(MAGal)are separately polymerized with Sodium 4-vinylbenzenesulfonate(SS)to form copolymers through RAFT polymerization,then the terminal groups are also reduced to thiol group.The two copolymers are separately mixed with terminal thiolated poly(2-(methacryloyloxy)ethyl trimethylammonium iodide)(p METAI)and immobilized onto GNPL.The polymer immobilized GNPL is intended to kill Escherichia coli and promote neural differentiation of mouse embryonic stem cells(m ESC).The results show that this surface could adhere and kill Escherichia coli effectively with ability to support the growth of mouse embryonic stem cells(m ESC).3,Chitosan is crosslinked with glutaraldehyde to prepare the chitosan membrane.Meanwhile,chitosan is sulfated and the prepared 6-O-sulfated chitosan is further crosslinked onto the chitosan membrane surface to form the 6S chitosan membrane.The 6S chitosan membrane show universal antibacterial activity against both Escherichia coli and Staphylococcus aureus,and the antibacterial activity rises along with the increase in the concentration of 6-O-sulfated chitosan applied.The number of Hela cells adhered on the 6S chitosan membrane is also kept at a relatively low level when 6-O-sulfated chitosan is conjugated at the highest concentration.In conclusion,several surfaces(gold nanoparticle,gold nanoparticle layer & chitosan membrane)are successfully modified with synthesized polymer and modified natural polysaccharide.These modified surfaces all show good antibacterial activity and biocompatibility.Also,other functions,such as promoting/inhibiting cell adhesion and inducing cell differentiation,are further introduced based on the modification routes.The preparation of these multi-functional interfaces show several examples for the design of novel antibacterial agents and biomaterials,which is promoting to be applied in pharmaceutical care,medical devices,etc.