Amperometric Biosensor for the Sensitive Detection of Plasmodium falciparum Histidine Rich Protein-2 Antigen

An electrochemical immunosensor based on the disposable screen-printed electrodes (SPEs) has been developed for the detection of Plasmodium falciparum histidine rich protein-2 (PfHRP-2) antigen. The immunosensor was employed in sandwich enzyme linked immunosorbent assay (ELISA) format involving rabbit anti-PfHRP-2 (capturing antibody) and mouse anti-PfHRP-2 (revealing antibody) and goat anti-mouse IgG-alkaline phosphatase (AP) conjugate. p-Aminophenyl phosphate (p-APP) was used as substrate and the amperometric response was measured as a function of concentration of p-aminophenol in 0.1 M diethanolamine (DEA) buffer solution, pH 9.0 at a potential of +150 mV versus Ag/AgCl reference electrode. The electrochemical detection can be done within 1 min and the total assay time was 55 min. The calculated detection limits for the electrochemical detection and the enzyme linked immunosorbent assay (ELISA) procedure are 60 ng/ml and 1 mu g/ml, respectively. The electrochemical immunosensor has higher sensitivity and faster than the standard spectrophotometric method.