An impedimetric immunosensor based on chitosan-Au nanoparticles-reduced graphene oxide nanosheet composite modified...

An ultrasensitive impedimetric immunosensor was developed to detect brain natriuretic peptide (BNP) for early diagnosis of heart failure. To construct this immunosensor, anti-BNP antibodies were immobilized covalently onto nanocomposite of chitosan-Au nanoparticles and reduced graphene oxide nanosheets (CHIT-Au@rGONs) electrodeposited onto pencil graphite electrode. This approach impedes charge transfer resistance (Rct) value proportionally to the BNP captured by antigen-antibody interactions. The observed Rct values by this immunosensor, were correlated with linear concentrations of BNP in the range, 1 × 10^-2 to 1 × 10³ pg/mL, with a limit of detection of 12 pg/mL and limit of quantification of 36.3 pg/mL. The immunosensor detected BNP in spiked human sera. The analytic recovery of added BNP in human sera was 97.04%. The present method was fairly consistent with commercial approach. The working electrode was stored for 2 months in cold. BSA-IgG had no interference in the electrode activity showing its high specificity for BNP. This novel approach provided a new POC-diagnostics, as direct sample measurements are easier and more efficient by this immunosensor compared to existing immunosensors.

The online version contains supplementary material available at 10.1007/s13205-023-03704-x.