A novel electrochemiluminescent immunosensor for the detection of NT-proBNP based on a Au/ZIF-67 nanocomposite

A new type of immunosensor was prepared by using a gold nanoparticles/aminozeolitic imidazolate framework-67 nanocomposite (AuNPs/ZIF-67) as the sensing matrix and luminol as the signaling probe to detect the heart failure biomarker N-terminal probrain natriuretic peptide (NT-proBNP). The hybrid nanocomposite was deposited on the surface of indium tin oxide (ITO)-coated glass via the linkage of 3-aminopropyltrimethoxysilane (APTMS); thereafter, the NT-proBNP antibody was immobilized to endow biological specificity, and bovine serum albumin was used to block residual active sites. The resultant sensor has an excellent response when NT-proBNP was attached to the antibody via immunoreaction; here, the output signal was reduced because of the depressed mass transportation of the electrochemiluminescence (ECL) probe and electron transference. The resultant ECL immunosensor displayed a broad linear range from 10 pg/mL to 50 ng/mL, and the low detection limit was 0.74 pg/mL. The ECL immunosensor also has good specificity, stability and reproducibility and can be used to detect NT-proBNP in real blood samples.