Synthesis Of Copper Nanoclusters Towards Bio-chemical Analysis And Improving The Antibacterial Activity

With the continuous development in recent years,the size of metal nanoclusters?MNCs?is generally less than 2 nm,and its unique atomic space configuration leads to the physical and chemical properties of the metal nanoclusters,such as:Photoluminescence?PL?effect,strong light stability,biocompatibility and catalytic performance,so the MNCs has aroused the concern of many scholars.These excellent properties and unique fluorescent make it well suited for biomarker applications.In addition,the different wavelength of metal nanoclusters ensure that they are well used in more complex environments,which is an important direction for future research.Copper has abundant reserves in nature,and experimental studies on copper nanoclusters have been reported in succession and demonstrate that they also have excellent fluorescence properties.However,compared to gold,silver and other metals,Cu is easily oxidized easily,so the study of copper nanoclusters still needs exploration in order to obtain Cu NCs with excellent fluorescence properties.Therefore,in this paper,two kinds of copper nanoclusters with excellent fluorescence properties were successfully synthesized by simple methods.Then,through the characterization of the Cu NCs to explore its formation mechanism and unique nature,targeted to its application in different directions.Expanding the application of copper nanoclusters and showing good values.The specific research contents are listed as follows:1. Papain-functionalized Cu nanoclusters?Cu NCs@Papain?were originally synthesized in aqueous solution together with a quantum yield of 14.3%,and showed obviously red fluorescence at 620 nm.Meanwhile,their corresponding fluorescence mechanism was detailly elucidated by Fluorescence,HR-TEM,FT-IR,and XPS.Subsequently,the as-prepared Cu NCs were employed as probes for detecting H₂O₂.Using Cu NCs as probes,H₂O₂ was determined in the range from 1?M to 50?M based on a linear decrease of fluorescence intensity as well as a detection limit of 0.2?M with a signal-to-noise ratio of 3.More significantly,it has been proved that Cu NCs could convert H₂O₂ to·OH,which conferred a dramatically antibacterial activity.Both in vitro and in vivo experiments were performed to validate its antibacterial activity against Gram-positive/negative bacteria and actual wound infection,suggesting its potential for serving as one type of promising antibacterial material.2.A facile way to synthesize Cu nanoclusters?Cu NCs?has been proposed while insulin played the role as a stabilizer.Specifically,this type of Cu NCs existed in tunable diameters of 4-5 nm,and exhibited bright reddish-orange fluorescence with a quantum yield of 7.4%.Interestingly,the fluorescence intensity of Cu NCs could be obviously enhanced and more stable by introducing Eu³⁺.Moreover,this proposed Eu³⁺@Cu NCs with low toxicity and near infra-red fluorescence may provide potential to broaden avenues for various applications in bioimaging and beyond.The above experimental results will help us to better understand the copper nanoclusters,and enlarge their applications in bio-chemical analysis.