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

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 beta-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 beta-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 beta-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.

  1. Center for Bio/Molecular Science and Engineering, Code 6910, US Naval Research Laboratory, Washington, DC 20375, USA
  2. Division of Optical Sciences, Code 5611, US Naval Research Laboratory, Washington, DC 20375, USA
  3. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
  4. Present address: Molecular Probes Inc., 29851 Willow Creek Road, Eugene, Oregon 97402, USA

Correspondence to: Hedi Mattoussi2 e-mail:

Correspondence to: J. Matthew Mauro1,4 e-mail: