PAPER: Quantum-dot/aptamer-based ultrasensitive multi-analyte electrochemical biosensor

Hansen, J. A.; Wang, J.; Kawde, A.-N.; Xiang, Y.; Gothelf, K. V.; Collins, G.

J. Am. Chem. Soc. 2006, 128, 2228–2229, doi: 10.1021/ja060005h

Departments of Chemical and Material Engineering and of Chemistry and Biochemistry, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-5801

Interdisciplinary Nanoscience Center (iNANO), Department of Chemistry, Langelandsgade 140, Aarhus University, 8000 Aarhus C, Denmark

Naval Research Laboratory, Chemistry Division, Washington, D.C. 20375

Abstract

The coupling of aptamers with the coding and amplification features of inorganic nanocrystals is shown for the first time to offer a highly sensitive and selective simultaneous bioelectronic detection of several protein targets. This is accomplished in a single-step displacement assay in connection to a self-assembled monolayer of several thiolated aptamers conjugated to proteins carrying different inorganic nanocrystals. Electrochemical stripping detection of the nondisplaced nanocrystal tracers results in a remarkably low (attomole) detection limit, that is, significantly lower than those of existing aptamer biosensors. The new device offers great promise for measuring a large panel of disease markers present at ultralow levels during early stages of the disease progress.