A Electrochemiluminescence Assay For H-FABP Based On Luminol Functionalized Two-dimensional Metal-organic Framework

The sensitive detection of disease biomarkers plays important role in the early diagnosis of the disease,which could effectively improve the survival rate and quality life of patients.Heart-type fatty acid binding protein（H-FABP）,as a novel biomarker of acute myocardial infarction（AMI）,can be released into the circulatory system and detected in blood samples within 90 minutes of myocardial injury.Compared with cardiac troponin T,the current clinically commonly used AMI biomarker,H-FABP has better timeliness.Therefore,accurate and sensitive detection of H-FABP has important value in the diagnosis and therapy of AMI.At present,enzyme-linked immunosorbent assay and chemiluminescence immunoassay are commonly used clinical H-FABP detection methods,but these methods require expensive instruments and professional technical personnel,and have complex operating procedures and limited sensitivity.Therefore,this work developed a simple and practical electrochemiluminescence immunosensing assay for highly sensitive and highly specific detection H–FABP,which based on the efficient self-enhanced solid-state luminophore strategy and the signal amplification effect of ultrathin two-dimensional Ni-TCPP（Fe）nanosheets.In this work,we synthesized a novel ultrathin Ni-TCPP（Fe）nanosheet with high specific surface area and abundant active sites.It has excellent peroxidase mimic activity so as to effectively accelerate the oxidation and decomposition of H₂O₂,resulting the amplified ECL signal of luminol.Moreover,Ni-TCPP（Fe）nanosheets can as an ideal nanocarrier to simultaneously immobilize PEI and luminol,thus constructing a self-enhanced solid-state luminophore（Ni-TCPP（Fe）-PEI-Lum）,possessing higher ECL efficiency and favourable stability.In addition,poly（indole-5-carboxylic acid）（PICA）,which has excellent conductivity and abundant binding sites,was used as the electrode substrate to immobilize a large number of primary antibodies,further improving the sensitivity.Under optimal conditions,the designed ECL immunosensor exhibited a wide dynamic range of 100 fg m L^-1～100 ng m L^-1and a detection limit as low as 44.5 fg m L^-1.In addition,the ECL immunosensor behaved excellent specificity and desirable stability,and was successfully applied to detect target H-FABP protein in serum sample.The simple and sensitive electrochemiluminescence immunoassay not only provides a new analytical method for the detection of biomarkers in clinical laboratory diagnosis,but also expands the application potential of two-dimensional MOF nanosheets in ECL technique.