Speaker
Description
Linear and ultrafast optical techniques (including Raman, Infrared and Uv/Vis spectroscopy) are excellent tools to investigate molecular structure and dynamics in solution. However, these spectroscopic methods are generally not sensitive to the size of molecules. Inspired by concepts from NMR, we have developed a spectroscopic method that adds a size dimension to optical spectra: optical Diffusion-Ordered Spectroscopy (DOSY). In an optical DOSY spectrum, the(2D)Infrared (1) or Raman (2) or Uv/Vis (3) spectrum is spread out along an additional axis showing the diffusion coefficient (or equivalently, size). The combined sensitivity to spectroscopic signature and diffusion coefficient is achieved by generating a concentration gradient inside a specially designed sample cell and monitoring its equilibration in a spectrally and time-resolved manner. The resulting multi-dimensional DOSY spectrum has Raman or IR frequency or Uv/Vis wavelength on the first axis/axes, and the diffusion coefficient (or size) on the other axis. We are currently exploring a broad range of applications, ranging from investigating ultrasmall nanoparticles and supramolecular complexes to studying amyloids and contaminants in protein solutions.
We believe that optical DOSY will become a valuable tool for investigating structure and dynamics of molecules, aggregates and particles in solution, by providing the size (or size distribution) and unraveling the (multidimensional) optical spectra of mixed solutions.
