A self-assembled quantum dot probe for detecting β-lactamase activity

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)931-935
Journal / PublicationBiochemical and Biophysical Research Communications
Issue number3
Online published19 Apr 2006
Publication statusPublished - 9 Jun 2006
Externally publishedYes


This communication describes a quantum dot probe that can be activated by a reporter enzyme, β-lactamase. Our design is based on the principle of fluorescence resonance energy transfer (FRET). A biotinylated β-lactamase substrate was labeled with a carbocyanine dye, Cy5, and immobilized on the surface of quantum dots through the binding of biotin to streptavidin pre-coated on the quantum dots. In assembling this nanoprobe, we have found that both the distance between substrates and the quantum dot surface, and the density of substrates are important for its function. The fluorescence emission from quantum dots can be efficiently quenched (up to 95%) by Cy5 due to FRET. Our final quantum dot probe, assembled with QD605 and 1:1 mixture of biotin and a Cy5-labeled lactam, can be activated by 32 μg/mL of β-lactamase with 4-fold increase in the fluorescence emission. © 2006 Elsevier Inc. All rights reserved.

Research Area(s)

  • β-Lactamase, Enzyme-activated probe, Fluorescence resonance energy transfer, Nanoparticle probe, Quantum dots, Self-assembly