Impedimetric immunosensor based on chitosan-modified gold wire with Au@rGO nanocomposite for the detection of brain natriuretic peptide (BNP)

The brain natriuretic peptide (BNP) is the most common and powerful cardiac biomarker for a range of diseases, especially heart failure (HF). To detect HF at early stage, we have developed an impedimetric immunosensor for measuring BNP levels in serum. The anti-BNP antibodies were immobilized on the surface of Au wire along with chitosan (CHIT), gold nanoparticles (AuNPs) and reduced graphene oxide (rGO) nanocomposite (CHIT-Au@rGO). All structural characterizations of electrode at different stages were performed using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and zeta-potential (Z-potential). The charge transfer resistance (Rct) values of working electrode showed linearity with BNP concentrations in the range of 1*10 –2 –1*10 3 pg/mL with a LOD score of 0.65 pg/mL and LOQ of 1.99 pg/mL, demonstrating the development of an improved BNP immunosensor, a potent biomarker for HF. The current immunosensor was successful in detection of BNP in spiked human serum samples. Analytic recovery of added BNP in human sera was 101.75%. There was no interference from BSA or IgG in measuring BNP by the present electrode, demonstrating the specificity of present BNP immunosensor. Graphical Abstract