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Proceedings Paper

Using metal complex-labeled peptides for charge transfer-based biosensing with semiconductor quantum dots
Author(s): Igor L. Medintz; Thomas Pons; Scott A. Trammell; Juan B. Blanco-Canosa; Philip E. Dawson; Hedi Mattoussi
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Paper Abstract

Luminescent colloidal semiconductor quantum dots (QDs) have unique optical and photonic properties and are highly sensitive to charge transfer in their surrounding environment. In this study we used synthetic peptides as physical bridges between CdSe-ZnS core-shell QDs and some of the most common redox-active metal complexes to understand the charge transfer interactions between the metal complexes and QDs. We found that QD emission underwent quenching that was highly dependent on the choice of metal complex used. We also found that quenching traces the valence or number of metal complexes brought into close proximity of the nanocrystal surface. Monitoring of the QD absorption bleaching in the presence of the metal complex provided insight into the charge transfer mechanism. The data suggest that two distinct charge transfer mechanisms can take place. One directly to the QD core states for neutral capping ligands and a second to surface states for negatively charged capping ligands. A basic understanding of the proximity driven charge-transfer and quenching interactions allowed us to construct proteolytic enzyme sensing assemblies with the QD-peptide-metal complex conjugates.

Paper Details

Date Published: 3 March 2009
PDF: 8 pages
Proc. SPIE 7189, Colloidal Quantum Dots for Biomedical Applications IV, 71890M (3 March 2009); doi: 10.1117/12.808537
Show Author Affiliations
Igor L. Medintz, U.S. Naval Research Lab. (United States)
Thomas Pons, U.S. Naval Research Lab. (United States)
Scott A. Trammell, U.S. Naval Research Lab. (United States)
Juan B. Blanco-Canosa, The Scripps Research Inst. (United States)
Philip E. Dawson, The Scripps Research Inst. (United States)
Hedi Mattoussi, U.S. Naval Research Lab. (United States)

Published in SPIE Proceedings Vol. 7189:
Colloidal Quantum Dots for Biomedical Applications IV
Marek Osinski; Thomas M. Jovin M.D.; Kenji Yamamoto M.D., Editor(s)

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