Biological Detection Method And Application Based On Metal Nanoclusters

Cancer and chronic illness threat the life and health of human being,which intensively influence the quality of life.The occurrence and development of disease is closely related to nuclear acids such as DNA andRNA,proteins,metal ions as well as small molecules.At the early stage of disease,the concentration of the markers is very low and difficult to be detected,which leads to miss the best opportunity of the treatment of disease.Therefore,it is of great significance to develop highly sensitive and specific detection method for early diagnose and real-time monitoring of disease.In this article,three sensitive methods for DNA?Fe³⁺?miRNA detection are developed using metal nanoclusters as labels.The main contents are as follows:1.Electrochemical detection of DNA based on copper nanocluster(CuNCs)-bio-barcode amplificationA high sensitive electrochemical biosensor was constructed based on bio-barcode amplification and the high affinity of polythymine(Poly T)with copper ions for the quantitative detection of gastric cancer DNA.The DNA-Si O₂-Poly T probes were prepared and the copper ions were reduced to copper nanoclusters along Poly T strands,resulting in the amplified detection of target DNAs.In optimal conditions,the ratio of capture probe to poly T was 1:60,and the optimal reducing time of copper ions was 10 min.The limit of detection of this method was 10 pM.The ratio of signals of background-substrated of complementary DNA:one-base mismatched DNA:two-base mismatched DNA:tatolly mismatched DNA was 5.3:3.7:1.9:1.This method is of good specificity.2.Fluorescent sensor based on Gold nanoclusters(AuNCs)for sensitive detection of Fe³⁺A simple and sensitive fluorescent sensor for Fe³⁺detection was established based on GSH-AuNCs which were prepared using glutathione(GSH)as the template.The sensor is very stable and sensitive in the pH range of 2?9.The optimal reaction time is 30 min and the reaction temperature is 15?.The limit of detection of this method was 2 n M,with linear relation of 0.005?15?M and good specificity.The range of recovery of urine was 91.5%?104.8%.This method is simple,fast and sensitive for Fe³⁺detection.3.Detection of miRNA based on non-labeled multiplex amplification of silver nanoclustersNon-labeled multiple amplification detection of miRNA-195 were developed based on the cascade catalytic hairpin assembly(CHA)and the aggregation-induced emission of silver nanoclusters.The hybrid H1-H2composite structure was continuously generated through the cascade CHA cycle,which brought the silver nanoclusters close to each other,resulting in the multiple amplification of fluorescence signals.The optimal reaction time was 6 h with optimal reaction temperature of 25?,and the optimal ion concentration of buffer was 300 mM of Na⁺.The detection limit for miRNA-195 was 300 pM,with good specificity.