Self-indicating nanobiosensor for detection of 2,4-dinitrophenol

A colorimetric nanobiosensor was developed based on the chromogenic effect of latex microspheres hybridization with gold nanoparticles. A toxin analog, 2,4-dinitrophenol–bovine serum albumin (DNP–BSA) was attached to gold nanoparticles and was allowed to hybridize via antigen–antibody association with an anti-DNP antibody on latex microspheres, changing the color of latex microspheres pinkish-red. A model toxin, DNP–glycine (GLY), was detected and quantified via a competition that occurs between the analog-conjugated-gold nanoparticles and the toxin molecules for the binding pocket in the anti-DNP antibody. When the gold nanoparticles were displaced from host latex microspheres in the presence of toxin molecules, a visible color change occurred from pinkish-red to white. This proof-of-concept self-indicating nanobiosensor detected the model toxin rapidly, and the results were quantifiable. When further developed, this nanobiosensor system will be useful at the consumer end to help improve food safety and counter possible bioterrorism attacks.