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RISS 인기검색어
- 검색키워드
- 저자 : Korystov, (검색결과 5 건)
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Polarity Probing Two-Photon Fluorophores Based on [2.2]Paracyclophane
Woo, Han-Young,Korystov, Dmitry,Jin, Young-Eup,Suh, Hong-Suk Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.12
A series of tetra donor substituted [2.2]paracyclophane-based two-photon absorption (TPA) fluorophores were synthesized in neutral and cationic forms. The imaging activity of overall set of fluorophores was studied by the two-photon induced fluorescence (TPIF) method in a range of solvents. We also measured a clear progression toward a longer photoluminescence lifetime with increasing solvent polarity (intrinsic photoluminescence lifetime, τi: ~2 ns in toluene → 12-16 ns in water). The paracyclophane fluorophores with this unique property can be utilized as an optical polarity probe for the biomolecular substrates. The combined measurement of the two-photon fluorescence microscopy (TPM) cell image and TPIF lifetime can give us a better understanding of the biological processes and local environments in the cells.
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Polarity Probing Two-Photon Fluorophores Based on [2.2]Paracyclophane
Han Young Woo*,Dmitry Korystov,진영읍,서홍석 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.12
A series of tetra donor substituted [2.2]paracyclophane-based two-photon absorption (TPA) fluorophores were synthesized in neutral and cationic forms. The imaging activity of overall set of fluorophores was studied by the two-photon induced fluorescence (TPIF) method in a range of solvents. We also measured a clear progression toward a longer photoluminescence lifetime with increasing solvent polarity (intrinsic photoluminescence lifetime, t i: ~2 ns in toluene 12-16 ns in water). The paracyclophane fluorophores with this unique property can be utilized as an optical polarity probe for the biomolecular substrates. The combined measurement of the two-photon fluorescence microscopy (TPM) cell image and TPIF lifetime can give us a better understanding of the biological processes and local environments in the cells.
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Woo, H. Y.,Vak, D.,Korystov, D.,Mikhailovsky, A.,Bazan, G. C.,Kim, D.-Y. WILEY-VCH Verlag 2007 Advanced Functional Materials Vol.17 No.2
<P>Two water-soluble conjugated polyelectrolytes, poly(9,9′-bis(6-N,N,N-trimethylammoniumhexyl)fluorene-alt-1,4-(2,5-bis(6-N,N,N-trimethylammoniumhexyloxy))phenylene) tetrabromide (P1i) and poly((10,10′-bis(6-N,N,N-trimethylammoniumhexyl)-10H-spiro(anthracene-9,9′-fluorene))-alt-1,4-(2,5-bis(6-N,N,N-trimethylammoniumhexyloxy))phenylene) tetrabromide (P2i) are synthesized, characterized, and used in fluorescence resonance energy transfer (FRET) experiments with fluorescein-labeled single-stranded DNA (ssDNA-Fl). P1i and P2i have nearly identical &pgr;-conjugated backbones, as determined by cyclic voltammetry and UV-vis spectroscopy. The main structural difference is the presence of an anthracenyl substituent, orthogonal to the main chain in each of the P2i repeat units, which increases the average interchain separation in aggregated phases. It is possible to observe emission from ssDNA-Fl via FRET upon excitation of P2i. Fluorescein is not emissive within the ssDNA-Fl/P1i electrostatic complex, suggesting Fl emission quenching through photoinduced charge transfer (PCT). We propose that the presence of the anthracenyl “molecular bumper” in P2i increases the distance between optical partners, which decreases PCT more acutely relative to FRET.</P> <B>Graphic Abstract</B> <P>Two cationic conjugated polyelectrolytes (CCPs, see figure) with similar optical/electronic properties but different molecular structures act as fluorescence resonance energy transfer (FRET) donors to fluorescein (FL)-labeled single-stranded DNA. Comparison of their efficiencies of energy transfer indicates that backbone modification with “molecular bumpers” fine-tunes the competition between FRET and photoinduced charge-transfer (PCT) mechanisms. <img src='wiley_img/1616301X-2007-17-2-ADFM200600093-content.gif' alt='wiley_img/1616301X-2007-17-2-ADFM200600093-content'> </P>
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Nayak, R.R.,Nag, O.K.,Woo, H.Y.,Hwang, S.,Vak, D.,Korystov, D.,Jin, Y.,Suh, H. Elsevier 2009 CURRENT APPLIED PHYSICS Vol.9 No.3
Two cationic conjugated polyelectrolytes (CPs, P1i and P2i) were synthesized and examined as a fluorescence resonance energy transfer (FRET) donor to fluorescein (Fl)-labeled single-stranded DNA (ssDNA-Fl) using steady-state and time-resolved photoluminescence (PL) spectroscopy. The two polymers have the same π-conjugation with the main structural difference being the presence of the spiro-anthracenyl substituents orthogonal to the polymer backbone of P2i. These spiro-substituents can function as a molecular spacer that increases the intermolecular separation in the electrostatic complex with ssDNA-Fl. We measured almost complete PL quenching of the excited Fl* after electrostatic complexation with P1i (PL lifetime 4ns->78ps) and relatively moderate quenching with P2i (PL lifetime 4ns->552ps). A quenching efficiency (Φ<SUB>eT</SUB>) of 98% and 86% was obtained for P1i/ssDNA-Fl and for P2i/ssDNA-Fl, respectively. Both systems have same thermodynamic driving force for quenching as a result of them having the same electronic structures. This discrepancy can be explained in terms of the reduced quenching (via electron transfer, eT) by the increased D-A distance due to the existence of spiro-attached molecular spacers in P2i. It shows that thermodynamically favorable eT quenching can be controlled kinetically by modulating the D-A intermolecular distance using molecular spacers, which suggests an important molecular design guideline for efficient CPs-based DNA detection.
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Rati Ranjan Nayak,Okhil Kumar Nag,Han Young Woo*,황승구,Doojin Vak,Dmitry Korystov,진영읍,서홍석 한국물리학회 2009 Current Applied Physics Vol.9 No.3
Two cationic conjugated polyelectrolytes (CPs, P1i and P2i) were ynthesized and examined as a fluorescence resonance energy transfer (FRET) donor to fluorescein (Fl)-labeled single-stranded DNA (ssDNA–Fl) using steady-state and time-resolved photoluminescence (PL) spectroscopy. The two polymers have the same p-conjugation with the main structural difference being the presence of the spiro-anthracenyl substituents orthogonal to the polymer backbone of P2i. These spiro-substituents can function as a molecular spacer that increases the intermolecular separation in the electrostatic complex with ssDNA–Fl. We measured almost complete PL quenching of the excited Fl* after electrostatic complexation with P1i (PL lifetime 4 ns→78 ps) and relatively moderate quenching with P2i (PL lifetime 4 ns→552 ps). A quenching efficiency (ΦeT) of 98% and 86% was obtained for P1i/ssDNA–Fl and for P2i/ssDNA–Fl, respectively. Both systems have same thermodynamic driving force for quenching as a result of them having the same electronic structures. This discrepancy can be explained in terms of the reduced quenching (via electron transfer, eT) by the increased D–A distance due to the existence of spiro-attached molecular spacers in P2i. It shows that thermodynamically favorable eT quenching can be controlled kinetically by modulating the D–A intermolecular distance using molecular spacers, which suggests an important molecular design guideline for efficient CPs-based DNA detection.
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