Construction And Application Of G-quadruplex-specific Iridium Complex In Electrochemiluminescence Sensing Platform

The guanine(G)-quadruplex structure is a non-canonical DNA secondary structure consisting of a planar stack of four guanine residues stabilized by Hoogsteen hydrogen bonds.The G-quadruplex motif has rich structural polymorphism and flexibility,and has been widely used in the construction of analysis and detection platforms.Due to the interference of endogenous fluorophores in biological samples,luminescence analysis is often limited.Transition metal complexes have become probes for the detection of biomolecules due to their simple synthesis scheme,tunable excitation and emission maximums in the visible light region,long lifetime and large Stokes shift.attention.In particular,iridium complexes have recently been studied as G-quadruplex selective probes for the development of luminescent sensing platforms for a variety of targets.The specific research content is as follows:1.A new iridium(III)complex was found to have high selectivity to G-quadruplex DNA.A novel ECL sensor was constructed using the G-quadruplex selective iridium complex for sensitive recognition of ds DNA.Through experiments such as G-quadruplex fluorescent intercalator displacement(G4-FID),circular dichroism,electrophoresis,and cyclic voltammetry,the reaction products of each step are systematically characterized.Through experimental data,the quantitative identification of target ds DNA can be achieved by detecting the increased ECL signal of the G-quadruplex selective Ir(III)complex.Under the optimal experimental conditions,the prepared sensor can detect ds DNA with a wide linear range and a low detection limit.Finally,the sensor is effectively applied to the detection of target ds DNA in actual samples.2.An Ir complex was synthesized,and its ability as a selective probe for G-quadruplex was evaluated.The iridium complex has high selectivity to G-quadruplex DNA,and can be used to construct a label-free immunosensor detection method.Only when the target cardiac troponin I exists,GCE/GO@Au NPs/Ab1 can bind to Ab2-DNA Probe-Au NPs,the electrochemiluminescence signal is significantly enhanced,and the detection of c Tn I has a wide linear range and comparison.Low detection limit.And further testing in human serum samples.3.Hybrid chain reaction(HCR)and enzyme digestion cycle amplification strategies are the gold standard for low abundance detection.In order to expand the scope of application of HCR technology and new detection methods,we have developed a label-free ECL sensor that uses a G-quadruplex selective Ir complex composite luminescent probe for ultra-sensitive one-step detection of kanamycin.Under the optimal experimental conditions,the ECL sensor has a wide linear range and a low detection limit.This method was successfully used for kanamycin in food samples,indicating its potential application in biomolecular analysis.