Direct Electrochemiluminescent Immunosensor For Early Indication Of Coronary Heart Disease Using Dual Biomarkers

At present,the number of deaths due to coronary heart disease(CHD)in the world is high.Coronary heart disease often has organic lesions when diagnosed,which delays the opportunity for treatment and causes serious losses to the patient and his family.How to achieve early and sensitive detection of coronary heart disease has always been the direction of unremitting efforts of scientific researchers.We hope to find a new method to detect the markers of coronary heart disease and realize early warning of the disease,thereby reducing people's risk of disease.In this study,the determination of two biomarkers of coronary heart disease,low-density lipoprotein(LDL)and oxidized low-density lipoprotein(ox-LDL),was taken as the research goal.From the current commercial detection methods and published papers,the detection methods for LDL and ox-LDL are mainly enzyme-linked immunosorbent assay,nuclear magnetic resonance,tubular gel electrophoresis and high-performance liquid chromatography.These methods are not suitable for routine clinical or home tests due to their time-consuming operation,high testing costs and special fixed equipment.There is an urgent need to develop a tool that can perform POCT to achieve rapid,sensitive and low-cost detection of markers of CHD.This study successfully designed an unlabeled immunosensor based on Au-Co nanoparticles(Au-Co NPs)to detect these two biomarkers of coronary heart disease.Among them,gold-cobalt nanoparticles are obtained by a simple water-phase synthesis method,and their excellent conductivity provides an effective sensing platform for the sensor.The antibodies are then fixed to Au-Co NPs by Au-N or Au-S function on the indium tin oxide electrode to complete the sensor preparation.Using Luminol as a sensing probe,the electrochemical luminescence signal was significantly suppressed after the antigen and antibody formed an immune complex.Atomic force microscopy(AFM),electrochemical impedance spectroscopy(EIS),cyclic voltammetry(CV)and other methods were used to characterize the changes in the electrode surface after biomacromolecule binding.Under the optimized conditions,the immunosensor exhibited sensitive detection of LDL over a wide linear range from 0.420 to 100 pg mL-1 with a detection limit of 0.256 pg mL-1.Likewise,a linear regression of the concentration of ox-LDL was obtained over the range from 0.500 pg mL-1 to 60.0 pg mL-1,with a detection limit of 0.330 pg mL-1.The highly sensitive response of the above two biomarkers proves the efficiency and unique potential of immunosensors.This study provides a new method for the clinical diagnosis and early prevention of CHD and a tool for POCT.