| 초록 |
The solvent effects were studied in fluorescence resonance energy transfer (FRET) from a polyfluorene copolymer (FHQ, FPQ) to a fluorescein labeled ssDNA (ssDNA-Fl). Upon addition of dimethyl sulfoxide (DMSO), FRET signal was substantially enhanced with increasing DMSO content in DMSO/PBS mixtures. In the case of FHQ, FRET-induced Fl emission was seriously quenched in pure PBS, while increased FRET signal was observed in 80 vol% DMSO/PBS mixture (36.8 times higher than that in PBS). FPQ-sensitized FRET signal was also 3.8-fold amplified by the presence of DMSO. It is expected that DMSO alter the intermolecular distance by interrupting the hydrophobic interaction between polymers and DNA. From the experimental results such as of PL quenching constant and PL lifetime, we guess DMSO may induce loose complexation between the polymers and ssDNA-Fl, resulting in the changes of a fine-structure of CCPs/DNA complex with increment of the FRET-induced dye signal. |
