Immunosensing of NT-proBNP via Cu2+-based MOFs Biolabeling and in situ Microliter-Droplet Anodic Stripping Voltammetry

Immunoassay of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) was conducted using Cu2+-1,3,5-benzenetricarboxylic acid metal-organic frameworks (HKUST-1 MOFs) as the secondary antibody label, and in situ microliter-droplet anodic stripping voltammetry detection of Cu2+ in 0.1 M HNO3+1 M NaCl directly on the glassy carbon immunoelectrode. Electrochemical methods, quartz crystal microbalance, scanning electron microscopy and energy dispersive spectroscopy were employed for material and electrode characterizations. Under optimized conditions, the limit of detection (S/N=3) was 0.33 fg mL(-1), and the analysis of NT-proBNP in clinical serum samples returned good results.