Coupling of Optical tweezers with Tip-enhanced Raman Spectroscopy for single-molecule investigation of supramolecular systems

Descripción del proyecto

Un sistema doble abre una ventana a los enlaces supramoleculares

Las estructuras supramoleculares son moléculas muy grandes formadas por la agrupación o la unión de moléculas más pequeñas entre sí. A diferencia de la química convencional y los átomos unidos mediante enlaces covalentes, en química supramolecular suelen darse interacciones reversibles más débiles como las que son fundamentales para los sistemas y funciones biológicos. Los avances tecnológicos han hecho posible evaluar la fuerza mecánica de las interacciones no covalentes en sistemas monomoleculares. Sin embargo, hasta ahora ha sido imposible su caracterización química. El proyecto financiado con fondos europeos TweeTERS combina pinzas ópticas para obtener información mecánica con espectroscopia Raman de punta mejorada de última generación para obtener información química. El sistema permitirá realizar mediciones simultáneas de fenómenos de unión reversibles e identificar las especies moleculares que intervienen, las interacciones intermoleculares e intramoleculares y su orientación para manipular una sola molécula de sistemas supramoleculares con una resolución espacial sin precedentes.

Objetivo

Quantitative information on the dynamics and mechanistic principles behind supramolecular systems can be investigated in the single-molecule regime by measuring the nanometer displacements resulting from the application of picoNewton forces in optical trapping (OT) experiments. In particular, the mechanical strength of non-covalent interactions can be quantified when studying the reversible breaking/formation of hydrogen bonds on individual host-guest systems or the switching of a macrocycle between binding stations in a molecular shuttle. However, the fundamental chemical mechanisms behind the obtained real-time operational kinetics are not accessible with OT experiments and fundamental questions about the physicochemical processes underlying real-operation remain unanswered.
The goal of this project is to merge OT for single-molecule optical force microscopy experiments with tip-enhaced Raman spectroscopy (TERS). TERS is a powerfull nearfield-based techinque based on the coupling of Raman spectroscopy and scanning probe microscopy. It provides chemical characterization with single molecule sensitivity and few-nm spatial resolution. Since Raman spectroscopy is sensitive to molecular species, inter and intra molecular interactions and orientations; by combining OT-optical force microscopy with TERS, we will access the underlying physicochemical processes triggering specific shuttling events in molecular motors and other types of supramolecular systems. In particular, we aim to create a hybrid tool that can disentangle the relation between mechanical, conformational and chemical properties of individual synthetic supramolecular systems and the non-covalent interactions governing their behavior, with single-molecule sensitivity and spatial resolution in the range of 10 nm. TweeTERS will lead to a major technological improvement in the single-molecule manipulation field and in particular, in the nearly un-explored field of single-molecule supra-molecular chemistry.