1.Programa de Pós-Gradua??o em Bioquímica e Fisiologia,Universidade Federal de Pernambuco,Recife,Brazil;2.Programa de Pós-Gradua??o em Inova??o Terapêutica,Universidade Federal de Pernambuco,Recife,Brazil;3.Departamento de Bioquímica,Universidade Federal de Pernambuco,Recife,Brazil
Abstract:
The authors describe a label-free electrochemical biosensor based on CNTs for picogram range detection of the food carcinogen aflatoxin B1 (AFB1). A gold electrode was modified with a cysteine (Cys) self-assembled layer, and carboxyl-functionalized carbon nanotubes were covalently attached to Cys for the subsequent tethering of antibody against AFB1 (anti-AFB1). Topographical images of the biosensor surface were acquired by atomic force microscopy throughout the modification and assay procedure. Upon exposure to samples containing AFB1, its binding to anti-AFB1 will result in a change in electrical conductivity. The use of CNT warrants enhanced electrical properties, and the charge-transfer resistance (Rct) can be related to the concentration of AFB1. Biosensor selectivity was tested by using samples containing ochratoxin A. The electrode displays a limit of detection as low as 0.79 pg·g?1, and response is linear in the 0.1 to 20 pg·g?1 concentration range. The assay was applied to the determination of AFB1 in contaminated corn flour at concentrations so low that they cannot be quantified by established ELISAs. In our perception, this method represents a viable point-of-care probe for detection of AFB1.
Graphical abstract A gold electrode was modified with a cysteine self-assembled layer, and carboxyl-functionalized carbon nanotubes were covalently attached to cysteine for the subsequent tethering of antibody against AFB1. The assay was applied to the determination of AFB1 in contaminated corn flour.
