Jaba Saha

Investigation of Fluorescence Resonance Energy Transfer between Fluorescein and Rhodamine 6G

Fluorescence Resonance Energy Transfer between two organic dyes Fluorescein and Rhodamine 6G was investigated in aqueous solution in presence and absence of synthetic clay laponite. Spectroscopic studies suggest that both the dyes were present mainly as monomer in solution. Fluorescence Resonance Energy Transfer occurred from Fluorescein to Rhodamine 6G in solutions. Energy transfer efficiency increases in presence of laponite and the maximum efficiency was 72.00% in aqueous laponite dispersion. Energy transfer efficiency was found to be pH sensitive. It has been demonstrated that with proper calibration it is possible to use the present system under investigation to sense pH over a wide range from 1.5 to 8.0.

Development of a sensor to study the DNA conformation using molecular logic gates

This communication reports our investigations on the Fluorescence Resonance Energy Transfer (FRET) between two laser dyes Acriflavine and Rhodamine B in absence and presence of DNA at different pH. It has been observed that energy transfer efficiency is largely affected by the presence of DNA as well as the pH of the system. It is well known that with increase in pH, DNA conformation changes from double stranded to single stranded (denaturation) and finally form random coil. Based on our experimental results two different types of molecular logic gates namely, XOR and OR logic have been demonstrated which can be used to have an idea about DNA conformation in solution.

Effect of Zinc oxide nanoparticle on Fluorescence Resonance Energy transfer between Fluorescein and Rhodamine 6G

Fluorescence Resonance Energy Transfer between two dyes Fluorescein and Rhodamine 6G were investigated in solution in the presence and absence of Zinc oxide nanoparticle. Zinc oxide nanostructure is used as the fluorescence enhancing agent for the present study since donor (Fluorescein) fluorescence increase significantly in presence of nanoparticle. Accordingly, the energy transfer efficiency in the presence of nanoparticle increases. The maximum efficiency was 69% for acceptor (Rhodamine 6G) concentration of 0.75×10-5M. The energy transfer efficiency was found to be pH sensitive and it varies from 4.15% to 90.00% in mixed dye solution for a change in pH from 1.5 to 10.0. With proper calibration it is possible to use the present system under investigation to sense pH which is better with respect to our previous reported results [Spectrochim. Acta Part A. 149 (2015) 143-149] as it can sense a wide range of pH and with better sensitivity.

Effect of nano-clay platelet on fluorescence resonance energy transfer

This communication reports the phenomenon of fluorescence resonance energy transfer observed in between the binary solution of two laser dyes acriflavine (donor) and rhodamine B (acceptor), with and without nano-clay (laponite). It was observed that presence of clay particles increases the energy transfer efficiency. The effect of acceptor concentration on the total energy transfer efficiency has been studied to quantify the energy transfer, which may be used for photon emission and enhancement in lasing efficiency.