Counterion effects on fluorescence energy transfer in conjugated polyelectrolyte-based DNA detection

Okhil Kumar Nag, Mijeong Kang, Sungu Hwang, Hongsuk Suh, Han Young Woo

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Cationic poly[9,9'-bis[6"-(Af,Af,Af-)hexyl]fluorene-co-a/f-phenylene]s with five different counterions (CIs) were synthesized and studied as fluorescence resonance energy transfer (FRET) donors (D) to dye-labeled DNA (FRET acceptor, A). The polymers with different CIs show same π-conjugated electronic structure with similar absorption (λabs = ∼380 nm) and photoluminescence (λPL = ∼420 nm) emission spectra in water. The CIs accompanying the polymer chain are expected to affect the D/A complexation and modify the D-A intermseparation by acting as a spacer. Polymers with different CIs function differently as FRET excitation donors to fluorescein (Fl)-labeled single-stranded DNA (ssDNA-Fl). The FRET-induced Fl emission was enhanced significantly by the larger Cl-exchapolymers. The polymers with the CIs of tetrakis(l-imidazolyl)borate (FPQ-IB) and tetraphenylborate (FPQ-PB) showed a 2-4-fold enhancement in the FRET-induced signal compared with the polymer with bromide (FPQ-BR). The delayed FRET signal saturation an low association constants (Ka) with ssDNA-Fl (3.53 × 106 M-1 for FPQ-BR and 1.80 × 106 M-1 for FPQ-PB) were measured for the polymers with larger CIs. The delayed acceptor saturation strengthens the antenna effect and reduces self-quenching of F by increasing the polymer concentration near Fl. The weak polymer/ssDNA-Fl association reduces the amount of energy-wasting charge transfer by increasing D-A intermolecular separation. The combined effects lead to increase the overall FRET-induced signal.

Original languageEnglish
Pages (from-to)5788-5793
Number of pages6
JournalJournal of Physical Chemistry B
Volume113
Issue number17
DOIs
Publication statusPublished - 2009 Apr 30
Externally publishedYes

Fingerprint

Energy Transfer
Fluorescence Resonance Energy Transfer
Polyelectrolytes
Energy transfer
resonance fluorescence
Polymers
DNA
deoxyribonucleic acid
Fluorescence
Fluorescein
energy transfer
fluorescence
polymers
Tetraphenylborate
Association reactions
saturation
Borates
Single-Stranded DNA
borates
Complexation

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Counterion effects on fluorescence energy transfer in conjugated polyelectrolyte-based DNA detection. / Nag, Okhil Kumar; Kang, Mijeong; Hwang, Sungu; Suh, Hongsuk; Woo, Han Young.

In: Journal of Physical Chemistry B, Vol. 113, No. 17, 30.04.2009, p. 5788-5793.

Research output: Contribution to journalArticle

Nag, Okhil Kumar ; Kang, Mijeong ; Hwang, Sungu ; Suh, Hongsuk ; Woo, Han Young. / Counterion effects on fluorescence energy transfer in conjugated polyelectrolyte-based DNA detection. In: Journal of Physical Chemistry B. 2009 ; Vol. 113, No. 17. pp. 5788-5793.
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