Semiconductor quantum dots (QD) are a class of NP with photophysical properties that are ideally suited for optical multiplexing and use as donors in fluorescence resonance energy transfer (FRET). A new strategy is presented for the development of multiplexed DNA hybridization assays using immobilized QDs in a microfluidic system. Green- or red-emitting QDs were immobilized via self-assembly with a multidentate-thiol-derivatized glass slide, and subsequently conjugated with amine-terminated probe oligonucleotides using carbodiimide activation. Immobilized QD-probe conjugates were then passivated with adsorbed non-complementary oligonucleotides to achieve selectivity in microfluidic assays. Target nucleic acid sequences hybridized with QD-probe conjugates and were labeled with Cy3 or Alexa Fluor 647 as acceptor dyes for the QD donors, where FRET-sensitized dye emission provided a signal for the detection of picomolar quantities of target. The simultaneous immobilization of green- and red-emitting QDs at different ratios within a microfluidic channel was demonstrated as a step toward multiplexed assays.

Date Published: 11 February 2011
PDF: 11 pages
Proc. SPIE 7909, Colloidal Quantum Dots/Nanocrystals for Biomedical Applications VI, 79090X (11 February 2011); doi: 10.1117/12.877326

Published in SPIE Proceedings Vol. 7909:
Colloidal Quantum Dots/Nanocrystals for Biomedical Applications VI
Wolfgang J. Parak; Kenji Yamamoto M.D.; Marek Osinski, Editor(s)