Proline Enhances The Antibacterial Activity And Mechanism Of His@AuNCs And Cyt@AuNCs

Bacteria and other microorganisms have had a serious impact on human health for along time.Nanozymes have become a new generation of antibiotics due to their broad-spectrum antibacterial activity,negligible toxicity and lack of drug resistance to bacteria.However,compared with natural enzymes,the catalytic activity of nanozymes is relatively low,which severely limits the antibacterial properties of almost all nanozymes.In order to improve the antibacterial activity of nanoenzymes,the adjustment of its inherent properties is favored by scientific researchers.However,developing and designing of high-performance nanoenzymes has certain challenges.Therefore,the development of a simple,fast and inexpensive antibacterial strategy is of great significance in the field of antibacterial.Existing reports have proved that natural organic matter can affect the physical and chemical properties and biological activities of nanomaterials.Therefore,through the interaction of these substances with nanomaterials,the inhibition of bacterial growth can be achieved.Based on this,this study reports that,in the presence of proline,His@AuNCs and Cyt@AuNCs have antibacterial effects on Gram-negative bacteria E.coli and Gram-positive bacteria S.aureus,and increase proline the mechanism of antibacterial activity of His@AuNCs and Cyt@AuNCs was studied.The main content and conclusions are as follows:1.His@AuNCs peroxidase-like activity and mechanism.Firstly,successful synthesized His@AuNCs can respond to a typical catalytic substrate（including TMB,OPD and ABTS）of peroxidase-like.Secondly,the His@AuNCs peroxidase-like activity presents a typical Michaelis-Menten curve.Finally,the experiment of capturing free radicals by TA proves that the catalytic mechanism of His@AuNCs peroxidase-like activity is due to its ability to catalyze H₂O₂ production·OH.2.Analysis of the antibacterial performance of His@AuNCs and Cyt@AuNCsOn the basis of the previous part,the antibacterial effects of His@AuNCs and Cyt@AuNCs were discussed.The results show that both nanozymes have certain inhibitory bacterial growth ability,providing a foundation for such materials as a bacteriostainion.3.Influence of proline on His@AuNCs and Cyt@AuNCs antibacterial behaviorFirstly,proline can enhance the antibacterial activity of His@AuNCs and Cyt@AuNCs.Secondly,the antibacterial activity of proline-enhanced His@AuNCs and Cyt@AuNCs is caused by elevated ROS levels in bacterial cells.At the same time,proline has no effect on His@AuNCs and Cyt@AuNCs analogue activity,so that the increase in intracellular ROS level is caused by proline extracellular ROS more entered into the cell.In summary:this paper uses proline as an exogenous adjuvant,without affecting the His@AuNCs and Cyt@AuNCs simulation of peroxidase activity,by promoting the extracellular ROS of bacteria to enter the cells,the antibacterial activity of these two nanozymes was effectively enhanced,which provided a new idea for the further development and design of new antimicrobial agents.