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 language | English |
|---|---|
| Pages (from-to) | 5788-5793 |
| Number of pages | 6 |
| Journal | Journal of Physical Chemistry B |
| Volume | 113 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - 2009 Apr 30 |
| Externally published | Yes |
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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 journal › Article
}
TY - JOUR
T1 - Counterion effects on fluorescence energy transfer in conjugated polyelectrolyte-based DNA detection
AU - Nag, Okhil Kumar
AU - Kang, Mijeong
AU - Hwang, Sungu
AU - Suh, Hongsuk
AU - Woo, Han Young
PY - 2009/4/30
Y1 - 2009/4/30
N2 - 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.
AB - 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.
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U2 - 10.1021/jp8107733
DO - 10.1021/jp8107733
M3 - Article
VL - 113
SP - 5788
EP - 5793
JO - Journal of Physical Chemistry B Materials
JF - Journal of Physical Chemistry B Materials
SN - 1520-6106
IS - 17
ER -