Ultrafast molecular rotor based DNA sensor: An insight into the mode of interaction
•Understanding the interaction between ultrafast molecular rotor based sensor with natural DNA.•High sensitivity of ultrafast molecular rotor towards DNA is due to reduction in the torsional motion in its excited state.•The intercalation of sensor in DNA leads to large increase in its excited state lifetime.
Benzothiazole based ultrafast molecular rotor, Thioflavin T (ThT), is a well known fluorescence sensor for nucleic acids. Thus, the knowledge of mode of interaction between ThT and DNA is very important for efficient utilization of such fluorescence sensors. In the present article, we have reported detail studies on the mode of interaction between ThT and a natural DNA using steady-state and femtosecond time-resolved transient emission techniques. Detail steady-state studies show that ThT binds strongly with natural DNA and causes a large change in its spectroscopic properties. Femtosecond transient emission studies show a substantial decrease in the torsional motion in the excited state of ThT bound to DNA molecules, indicating a strong interaction between them. It is observed that ThT binds to DNA through two modes of interaction. Studies with salt indicate that large fraction of ThT binds to DNA by electrostatic interaction, whereas, viscosity and resonance energy transfer studies indicate the intercalation of ThT with DNA molecules.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideMode of interaction between UMR and DNA.
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 295, 1 December 2014, Pages 17–25