Raman Signal Enhancement by DABCYL-Substitution on DNA Aptamer for Identification of Cellular ATP.

Raman probes have attracted widespread attention for the visualization and identification of biomolecules, because they can be applied to identify detailed chemical structures, detect multiple molecules simultaneously, and visualize cellular functional molecules. However, the biological application of Raman probes is still limited because of their weak signal intensity. Herein, we present a molecular system that shows an enhanced Raman signal using a nonfluorescent dye. We introduced a DABCYL molecule bearing an acetylene unit into thymidine at the 5-position. The resulting modified nucleobase, dU, showed a robust signal around 2200 cm, which was attributed to the acetylene unit, due to resonance Raman induced by the DABCYL group. We further prepared a DNA aptamer modified with dU, and characterized the change of the Raman spectra. Combination with gold nanoparticles, which enhanced the Raman signal by surface-enhanced Raman scattering (SERS), allowed sensitive detection of cellular adenosine derivatives including ATP. Thus, the present system is a promising tool for the detection of biological materials by Raman spectroscopy.