Self-assembled monolayer based impedimetric platform for food borne mycotoxin detection.
A self-assembled monolayer (SAM) of 11-amino-1-undecanethiol (AUT) has been fabricated onto a gold (Au) substrate to co-immobilize anti-ochratoxin-A antibodies (AO-IgGs) and bovine serum albumin (BSA) to detect food borne mycotoxin [i.e., ochratoxin-A (OTA)]. AUT/Au electrode, AO-IgGs/AUT/Au immunoelectrode and BSA/IgGs/AUT/Au immunoelectrode have been characterized using scanning electron microscopy (SEM) and electrochemical studies such as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Electrochemical studies reveal that the AUT-SAM with NH2 groups provide favorable conditions to immobilize AO-IgGs with better orientation, resulting in enhanced electron transport to obtain improved sensing characteristics. The EIS response studies of the BSA/AO-IgGs/AUT/Au immunoelectrode obtained as a function of OTA concentration reveal that the value of the charge transfer resistance (RCT) increases with increased OTA concentration. The BSA/AO-IgGs/AUT/Au immunoelectrode exhibits linearity over 0.5-6.0 ng/dl, detection limit of 0.08 ng/dl using 3σb/m criteria, response time of 30 s and sensitivity of ∼36.83 Ω/ng dl(-1) cm(-2) with a regression coefficient of 0.999. Attempts have been made to monitor the change in RCT of BSA/AO-IgGs/AUT/Au immunoelectrode on addition of coffee samples.
Department of Science and Technology Centre on Biomolecular Electronics, National Physical Laboratory (Council of Scientific Industrial Research), Dr K. S. Krishnan Marg, New Delhi, 110012, India. bansi.malhotra@gmail.com.
Pratima Rathee
PR
Solanki
Ajeet
A
Kaushik
T
T
Manaka
Manoj Kumar
MK
Pandey
M
M
Iwamoto
Ved Varun
VV
Agrawal
Bansi Dhar
BD
Malhotra
D000473:Alkanes / Q000737:chemistry; D000818:Animals; D055910:Antibodies, Immobilized / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods; D002417:Cattle; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D005506:Food Contamination / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D007118:Immunoassay / Q000379:methods*; D009793:Ochratoxins / Q000032:analysis*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry
C510729:11-amino-1-undecanethiol; D000473:Alkanes; D055910:Antibodies, Immobilized; D009793:Ochratoxins; D013438:Sulfhydryl Compounds; C025589:ochratoxin A; D012710:Serum Albumin, Bovine; D006046:Gold