Efficient Fluorescence (or Förster) Resonance Energy Transfer (FRET) pairs between fluorescent proteins and quantum dots (QDs) have a significant potential for ultrasensitive biochemical assays in disease detection and diagnosis. We have developed such FRET pairs using commercially available QDs as donors and fluorescent protein as acceptor, with polyhistidine-chelation as the means of bioconjugation. In this study we compared two brands of QDs with different surface coatings and found that the FRET pair containing EviTags from Evident Technology produced a higher FRET efficiency due to the shorter donor-acceptor distance. The polyhistidine binds directly to the ZnS capping layer of the EviTags, whereas the carboxyl QDots from Invitrogen, although having a higher quantum yield, require the addition of Ni²⁺ to the solution in order to facilitate chelation-mediated binding to outer surface of the polymer coating. These findings have significant implications to QD-based FRET assay design.

Date Published: 13 March 2008
PDF: 11 pages
Proc. SPIE 6866, Colloidal Quantum Dots for Biomedical Applications III, 68660C (13 March 2008); doi: 10.1117/12.763727

Published in SPIE Proceedings Vol. 6866:
Colloidal Quantum Dots for Biomedical Applications III
Marek Osinski; Thomas M. Jovin; Kenji Yamamoto, Editor(s)