Article abstract
Nature Materials 2, 630 - 638 (2003)
Published online: 24 August 2003 | doi:10.1038/nmat961
Subject Categories: Sensors and biosensors | Nanoscale materials
Self-assembled nanoscale biosensors based on quantum dot FRET donors
Igor L. Medintz1, Aaron R. Clapp2, Hedi Mattoussi2, Ellen R. Goldman1, Brent Fisher3 & J. Matthew Mauro1,4
Abstract
The potential of luminescent semiconductor quantum dots (QDs) to
enable development of hybrid inorganic-bioreceptor sensing materials has
remained largely unrealized. We report the design, formation and testing of
QD–protein assemblies that function as chemical sensors. In these
assemblies, multiple copies of Escherichia coli maltose-binding protein
(MBP) coordinate to each QD by a C-terminal oligohistidine segment and function
as sugar receptors. Sensors are self-assembled in solution in a controllable
manner. In one configuration, a 
-cyclodextrin-QSY9 dark quencher
conjugate bound in the MBP saccharide binding site results in fluorescence
resonance energy-transfer (FRET) quenching of QD photoluminescence. Added
maltose displaces the -cyclodextrin-QSY9, and QD photoluminescence
increases in a systematic manner. A second maltose sensor assembly consists of
QDs coupled with Cy3-labelled MBP bound to -cyclodextrin-Cy3.5. In this
case, the QD donor drives sensor function through a two-step FRET mechanism
that overcomes inherent QD donor–acceptor distance limitations. Quantum
dot–biomolecule assemblies constructed using these methods may facilitate
development of new hybrid sensing materials.
- Center for Bio/Molecular Science and Engineering, Code 6910, US Naval Research Laboratory, Washington, DC 20375, USA
- Division of Optical Sciences, Code 5611, US Naval Research Laboratory, Washington, DC 20375, USA
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Present address: Molecular Probes Inc., 29851 Willow Creek Road, Eugene, Oregon 97402, USA
Correspondence to: Hedi Mattoussi2 e-mail: hedimat@ccs.nrl.navy.mil
Correspondence to: J. Matthew Mauro1,4 e-mail: matt.mauro@probes.com
