A novel piezoelectric immunosensor for the detection of malarial Plasmodium falciparum histidine rich protein-2 antigen

A novel piezoelectric (PZ) immunosensor for the direct detection of malarial Plasmodium falciparum histidine rich protein-2 (PfHRP-2) antigen was developed. The mixed self-assembled monolayers (SAMs) of thioctic acid and 1-dodecanethiol were formed on gold surface of quartz crystal. Cyclic voltammetry, electrochemical impedance spectroscopy and surface Raman spectroscopy techniques were used to characterize the mixed SAMs. The rabbit anti-PfHRP-2 antibodies were coupled on mixed SAM modified gold surface of quartz crystal via NHS/EDC activation method. The PZ immunosensor was applied to detect PfHRP-2 in the linear range of 15-60 ng/ml with a detection limit of 12 ng/ml. It was also found that even after 14 days of storage, 50% of the activity still remained. Clinical human serum samples were tested with this method, and the results were in agreement with those obtained from commercially available ICT kit (NOW (R) Malaria). (C) 2011 Elsevier B.V. All rights reserved.