Tinku Basu
Amity Institute of Nanotechnology, India.
Title: Label free electrochemical piezoelectric immunosensor for aflatoxin B1 detection based on self-assembled thin film
Biography
Biography: Tinku Basu
Abstract
Aflatoxin B1 (AFB1), a potent carcinogenic mycotoxin, is of great concern due to their frequent occurrence in foods and their severe health effects on animals and humans. Immunosensor is tremendous potential tool for a real time, smart and reliable detection of AFB1. AFB1 being small and neutral molecule, label free detection of AFB1 in desired range is a challenge. A simple, label free electrochemical piezoelectric immunosensor based on monoclonal Aflatoxin B1 antibody (aAFB1) realized on self-assembled of 4-aminothiophenol monolayer on gold coated quartz crystal was developed for the detection of AFB1 with a LOD of 0.012ngmL-1 . The label free detection of AFB1 may perhaps be achieved due to perfect orientation of aAFB1 on the surface and aromatic П electron structure of 4-ATP providing a direct contact between the electrode and AFB1. Further attempt is made to enhance immunoresponse by employing two strategies (i) enhancement of electron transfer rate by inclusion of gold nanoparticles (AuNP) in the matrix and (ii) to follow a competitive sandwich protocol via metal nanoparticle-secondary antibody hybrid system. In the first approach, a multi layered immunoelectrode was designed by successive deposition of hexanedithiol (HDT), AuNP 3d network, cysteamine (cys) monolayer and finally covalently linked aAFB1 to fabricate BSA/aAFB1/Cys/AuNP/HDT/Au immunoelectrode with LOD of 8pg mL-1. A wide linear range coupled with LOD of 8pg mL-1 may be attributed to AuNP 3d network and perfect orientation of AFB1. In the second approach, an Au coated iron oxide core shell nanostructure- poly clonal antibody conjugate(r-IgG-Au-Fe3O4) was synthesized and a competitive sandwich mode was followed. The linear range of AFB1/BSA/aAFB1/4-ATP/Au immunosensor lay within from 0.05-5 ngmL-1 The unique feature of the immunosensor is its regeneration up to 15-16 times with 2-3% loss in activity using a strong external magnet(Fig.1). The BSA/aAFB1/4-ATP/Au immunoelectrode has been successfully utilized to detect AFB1 in contaminated groundnuts extract with the minimum error. The results as obtained by the electrode are in agreement with the LC-MS/MS results.