Publication 711

Anal. Chem. , 84 (12), 5415-5420, 2012 DOI:10.1021/ac301048c
Simple and Highly Enantioselective Electrochemical Aptamer-Based Binding Assay for Trace Detection of Chiral Compounds

ITODYS, UMR 7086 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 15 Rue Jean-Antoine de Baïf, F-75205 Paris Cedex 13, France
Laboratoire d’Electrochimie Moléculaire, UMR 7591 CNRS, Université Paris Diderot, Sorbonne Paris Cité, 15 Rue Jean-Antoine de Baïf, F-75205 Paris Cedex 13, France
Département de Pharmacochimie Moléculaire, UMR 5063 CNRS, Université Joseph-Fourier, 470 Rue De La Chimie, 38400 Saint-Martin d’Hères, France

A new electrochemical methodology is reported for monitoring in homogeneous solution the enantiospecific binding of a small chiral analyte to an aptamer. The principle relies on the difference of diffusion rates between the targeted molecule and the aptamer/target complex, and thus on the ability to more easily electrochemically detect the former over the latter in a homogeneous solution. This electrochemical detection strategy is significant because, in contrast to the common laborious and time-consuming heterogeneous binding approaches, it is based on a simple and fast homogeneous binding assay which does not call for an aptamer conformational change upon ligand binding. The methodology is here exemplified with the specific chiral recognition of trace amounts of L- or D-tyrosinamide by a 49-mer D- or L-deoxyribooligonucleotide receptor. Detection as low as 0.1% of the minor enantiomer in a nonracemic mixture can be achieved in a very short analysis time (<1 min). The assay finally combines numerous attractive features including simplicity, rapidity, low cost, flexibility, low volume samples (few microliters), and homogeneous format.