Preparation And Properties Of Ethylenediamine-modified Graphene/Ag Composite Antibacterial Agent

With the progress of society and the improvement of the people's living standards,people's pursuit of quality of life is also increasingly strong.However,with the rapid economic development,life has become more and more convenient,and people-to-people contacts have become more frequent,which has virtually increased the risk of bacterial transmission.The problem of bacterial resistance caused by the extensive use of antibacterial agents in clinics has become more and more serious.Many traditional antibacterial agents or antibacterial materials have been difficult to deal with drug-resistant or multi-drug resistant bacteria.In order to overcome bacterial resistance and meet the requirements of a wide range of bactericidal properties,the development of a broad-spectrum,high-efficiency,biocompatible antibacterial material has become an urgent task.Nanosilver particles have been widely used in the antibacterial field in recent years because of their advantages such as large specific surface area,extensive antibacterial properties,non-resistance,and good biocompatibility.However,nano silver particles are liable to agglomerate,making it difficult to transfer and assemble.In order to obtain nano silver having a uniform size and being easy to use,silver and graphene are composited,and in-situ reduction method is used to generate nano silver on the surface of graphene,and nano-silver particles can effectively synthesize graphene-loaded silver nano composite material with uniform dispersion..In this study,the surface modification of graphene oxide was carried out by using ethylenediamine to form a covalent bond between Ag particles and ethylenediamine grafted on the surface of graphene,so that the function of nano-Ag and graphene hybrid structure was sustained.The graphene-silver nanoparticle composites were formed in situ and the composites were characterized.The antibacterial effect of the graphene-loaded silver composite antibacterial agents against Staphylococcus aureus and Escherichia coli was studied.The main research contents and results of this paper are as follows:1.Graphene oxide?GO?was firstly prepared by a modified Hummers method;graphene oxide was used as a raw material,ethylenediamine was grafted onto the surface of graphene oxide under hydrothermal conditions,and AgNO₃ solution was used as the silver source.The method of bit reduction prepares a graphene-loaded silver composite antibacterial agent.XRD and FT-IR results showed that the graphene oxide surface was rich in oxygen-containing functional groups;XPS results showed that the Ag nanoparticles formed a covalent bond with the amino group on the graphene surface;SEM results showed that the graphene-loaded silver composite antibacterial agent was loaded on the surface.Nano silver particles have a particle size of about 30 nm and are uniformly dispersed without any agglomeration.2.The effects of the amount of ethylenediamine,modification time,AgNO₃concentration,complexation time and solution pH on the silver content of the composite antibacterial agent were investigated through orthogonal test.The results showed that AgNO₃ and graphite The olefin mole ratio>complexation time>ethylenediamine modification time>ethylenediamine content>system pH value,the optimal conditions for the preparation of ethylenediamine was 6.6 mL,the modified reaction time was 2.5 h;AgNO₃ and graphite The molar ratio of alkene is 0.13:1,the pH is 7.5 and the complexing time is 1.5 h.3.A series of antibacterial characterizations of the graphene-loaded silver composite antibacterial agents were performed using Gram-positive bacteria S.aureus and gram-negative bacteria E.coli as samples.Bacteria circle test and growth curve test.The antibacterial results showed that the graphene-loaded silver antimicrobial composites exhibited rapid and effective antibacterial properties against both E.coli and S.aureus.The minimum inhibitory concentration for E.coli is 8 mg/mL,and the minimum inhibitory concentration for S.aureus is 15 mg/mL.