Synthesis And Application Of Peptide-Metal Nanoclusters Fluorescence Sensor

As a new fluorescence nanomaterial,gold nanoclusters(AuNCs)are composed of several to one hundred gold atoms,which are generally less than 2 nm in diameter and have the properties of isolated atoms and nanoparticles.Metal nanoclusters have been widely used in many fields such as environment,biology and medical due to their excellent optical properties.This paper is devoted to the determination of allure red,insulin and thrombin by using fluorescence resonance energy transfer(FRET)between peptide-metal nanoclusters and cadmium sulfide(CdS)quantum dots.The main contents are as follows:1.The functional polypeptide(CCYRGHDHCY)was designed to modify gold nanoclusters(AuNCs),which were used to detect allura red.When allura red exists,the polypeptide and the allura red are mutually adsorbed by electrostatic attraction,and electron transfer occurs,resulting in aggregation of peptide-AuNCs,resulting in fluorescence quenching of the system.In the concentration range of 5-90?M,the allura red concentration has a good linear correlation with the quenching ratio.The linear equation is y=0.0164x+0.99073(R~2=0.998),and the detection limit is 0.667?mol/L.The fluorescence sensor can also be applied to detect the allura red in beverage sample.2.Based on the FRET between peptide-AuNCs and CdS quantum dots,a"turn on"sensing system using CdS quantum dots and CCYRRKRRHCY-AuNCs was designed to detect insulin.By quenching and recovering the fluorescence of the system,the insulin concentration could be sensitively detected.In the concentration range of 20-500 ng/mL,the insulin concentration has a good linear relationship with the fluorescence recovery ratio,the linear equation is y=12.359x+0.2591(R~2=0.996),and the detection limit is 6.67 ng/mL.This fluorescence sensing system was used to screen and quantify insulin in human serum samples.3.A"turn on"fluorescence sensing system was constructed based on FRET between functional peptide-silver nanoclusters(CCYRGWRGCY-AgNCs)and CdS quantum dots,and used for analytical detection of thrombin.Thrombin cleaves peptide bonds between arginine(R)and glycine(G)to specifically recognize peptide-AgNCs.Thrombin can attenuate FRET between peptide-AgNCs and CdS quantum dots to detect thrombin by quenching and recovery of system fluorescence.In the concentration range of 5-60 ng/mL,there has a good linear relationship between thrombin and fluorescence recovery ratio.The linear equation is y=0.0591x+0.0691(R~2=0.997),and the detection limit is 1.67 ng/mL.According to the efficiency of fluorescence recovery,thrombin can be effectively identified and detected,which can meet the needs of rapid screening of thrombin in serum samples.