Rhodamine-based dyes have been applied as chemosensors for in vivo detection of ions demonstrating superb ion sensitivity and selectivity. Moreover, Rhodamine-based dyes have attracted great attention in the surfaceenhanced Raman scattering (SERS) due to its large scattering cross-section allowing single-molecule detection without the necessity to create a plasmonic hotspot with a minimal gap distance, which is often referred to as Surface-enhanced Resonance Raman scattering (SERRS). Although some activated Rhodamine-based dyes are commercially available, they are very expensive, and the choices of the molecular structures which determine its ion-selectivity and sensitivity are limited. Within this context, it is imperative to develop a facile and versatile immobilization route of Rhodamine-based dyes onto plasmonic nanostructures for SERRS-based ion sensing. It is first necessary to study the interaction mechanisms between analyte and substrate to define an appropriate approach for a deeper understanding. T erefore, this project aims to find promising chemical linkers that can graft the Rhodamine-based dyes onto gold nanostructures without varying their ion sensitivity and selectivity via computational study on the structural, electronic, and reactivity properties Rhodaminebased dyes, followed by experimental proof of the calculation.This proposal refers to a collaborative work that involves the Center for Optics, Photonics and Lasers (COPL) of the Université Laval, CERVO Brain Research Centre of the Quebec Mental Health Institute, and the Health Division of the Center for Research and Development of Functional Materials (CDFM/CEPID/FAPESP 2013/07296-2). The present research proposal directly connects to the study of surface functionalization mechanisms of zwitterionic molecules, expanding for similar classes of molecules the understanding of the interaction between the molecule and surfaces for application in biological devices. Furthermore, the direct immobilization of the Rhodamine-based dyes through the chemical linker to be found in this study will broaden the choice of commercially available Xanthene-based dyes for the SERRS-based ion sensing and open a new avenue of chemosensor design.
News published in Agência FAPESP Newsletter about the scholarship: