Application And Preparation Of Au Nanosensor Based On Enzyme Kinetic Regulation Technology

ObjectiveUsing electrodeposition method,clusters of gold nanostructures were prepared under different environmental conditions,the effective reaction surface area of gold nanomaterials was increased across scales,and the biomolecular recognition efficiency of sensing interface of nanomaterials was accurately regulated,Sensitive detection of high expression of microRNA21 provides a method for accurate and rapid detection of abnormal expression of microRNA21 in gastric cancer tissues and provides a reference for accurate and rapid detection of biological molecules,exosomes,serum and other clinical targetsMethodsSix layers of polyacrylic acid?PAA?and polyethylene imine?PEI?were deposited on the SPCE by?i?applying a voltage of-0.8 V to-0.1 V to the electrodes;?ii?dropping 0.1 mg/ml to 1 mg/ml The chloroauric acid?HAuCl₄?;?iii?The deposition time of chloroauric acid is adjusted to 60s-1800s.Different gold nanostructures are prepared on the electrode surface,and the most ideal gold nanostructures are selected to construct high-performance cross-scale biological materials.Sense interface.The experiments were divided into E1 and E0 groups.The0.5?M thiol DNA21 with terminal methylene blue?MB?was assembled with a high-performance,cross-scale biosensor interface and a traditional smooth gold electrode interface.Results1.Depositing polyelectrolytes on SPCE:Compared with the latest published results,after the six layers of PAA/PEI were covered on SPCE,the stability of the constructed gold nanostructures was greatly enhanced and it was not easy to be washed by pure water.2.Construction of voltage regulation of gold nanostructures:Gold nanostructures deposited on the surface of SPCE are changed into spine-like spheres?layered floral patterns?clustered dendritic shapes.The best reaction voltage is-0.3V.3.Construction of HAuCl₄ concentration regulation of gold nanostructures:Gold nanostructures deposited on the surface of SPCE transition from hierarchical flower shape to nanomicrosphere morphology.The optimal HAuCl₄ deposition concentration was 0.3 mg/ml.4.Construction of reaction time regulation of gold nanostructures:The diameter of gold nanostructures deposited on the surface of SPCE changed from about 1.0?m initially to about 10?m.At the same time,these gold nanostructures retain intact nanostructured arms and branches throughout the deposition process.The best reaction time is 1200s.5.Enhanced interface enzyme kinetics:The efficiency of the DNA21/DNase I enzyme reaction of the SPCE sensor was 90%,whereas the efficiency of the DNA21/DNase I enzyme reaction of the conventional gold electrode sensor was only50%?P<0.05?.6.Sensitivity and specificity of the SPCE sensor:After detection and calculation,the detection limit of the SPCE sensor is as low as 10 aM.Response signal ratio of 0.5?M of DNA21-MB to 100fM of MicroRNA21/DSN(0.2 U mL^-1)is higher than that of single,two,and multiple base mismatched MicroRNA/DSN(0.2 U mL^-1)?P<0.05?.Conclusion1.High-curvature gold nanostructures were prepared on the surface of SPCE by"one-step"electrodeposition,which greatly increased the number of DNA probes assembled on the surface of SPCE.The electrochemical sensing interface organisms were precisely regulated by calculating the packing density of DNA probes.Molecular recognition efficiency.2.The high-performance cross-scale biosensor interface of SPCE provides a relatively high probe density and absolute number of molecules,exhibits a good spatial effect,greatly improves the possibility of intermolecular collision,and enhances the kinetics of interfacial enzymes.