Yingjie Zhang, University of Illinois Urbana-Champaign and QCB Faculty, will lecture on "Mid-Infrared Spectromicroscopy of Living Cells"
Abstract: Metabolite molecules, with a size typically less than 2 nanometers, are crucial in regulating cell functions. However, unlike our capability to localize and count single proteins and nucleic acids in biological systems, our ability to detect and quantify small molecules is significantly limited. Existing metabolomics tools are mainly restricted to mass spectrometry, which is incompatible with living cells, thus missing the dynamic metabolite profiles and their correlation with biological functions. To overcome this challenge, we have been developing a new method for chemical imaging of living cells. We utilize mid-infrared (mid-IR) spectroscopy for molecular fingerprinting and overcome the aqueous background absorption by coupling mid-IR light into optical fibers. By placing the fiber probes close to the targets, we collect full mid-IR spectrum of the regions of interest. I will discuss how this endoscopic mid-IR spectroscopy method has enabled the precise quantification of the local composition and concentration of small molecules in aqueous solution and inside living cells. At the end, I will further discuss our ongoing efforts to achieve full 3D spectromicroscopy of living cells at subcellular resolution.