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Proceedings Paper

DMSO effects on FRET to dye-labeled DNA in conjugated polymer-based DNA detection
Author(s): Mijeong Kang; Boram Kim; Han Young Woo
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Paper Abstract

Solvent effects were studied in fluorescence resonance energy transfer (FRET) from a cationic polyfluorene copolymer (FHQ, FPQ) to a fluorescein (Fl)-labeled oligonucleotide (ssDNA-Fl). Upon addition of dimethyl sulfoxide (DMSO), optical properties of the polymers and the probe dye were substantially modified. And the FRET-induced Fl emission was measured by directly exciting the polymer within the complex, polymer/ssDNA-Fl. The FRET signal was successfully modulated with changing the DMSO content. In the case of FHQ, the FRET-induced Fl emission was seriously quenched in phosphate buffer solution (PBS), while a salient FRET signal was observed in a 80 vol% DMSO/PBS mixture (36.8 time higher than that in PBS). The FPQ-sensitized FRET signal was also 3.8-fold amplified by the presence of DMSO. That result is from the decrease of hydrophobic interactions between the polymer and ssDNA-Fl, which induces the weaker polymer/ssDNA-Fl complexation with longer intermolecular separation. The gradual decrease in Fl PL quenching with increasing the DMSO content was investigated by measuring the Stern- Volmer quenching constants (3.3-4.2 × 106 M-1 in PBS, 0.56-1.1 x 106 M-1 in 80 vol% DMSO) in PBS/DMSO mixtures. The substantially reduced PL quenching would amplify the resulting FRET Fl signal. This approach suggests a simple way of modifying the fine-structure of polymer/ssDNA-Fl and improving the detection sensitivity in conjugated polymer-based FRET bioassays.

Paper Details

Date Published: 11 February 2011
PDF: 8 pages
Proc. SPIE 7908, Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications VIII, 790809 (11 February 2011); doi: 10.1117/12.874398
Show Author Affiliations
Mijeong Kang, Pusan National Univ. (Korea, Republic of)
Boram Kim, Pusan National Univ. (Korea, Republic of)
Han Young Woo, Pusan National Univ. (Korea, Republic of)

Published in SPIE Proceedings Vol. 7908:
Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications VIII
Alexander N. Cartwright; Dan V. Nicolau, Editor(s)

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