Dr. Yanyi Huang received his B.S. (Chemistry) and Sc.D. (Inorganic Chemistry) from Peking University in 1997 and 2002, respectively. He worked at Caltech with Amnon Yariv (Postdoc in Applied Physics) and then moved to Stanford with Stephen Quake (Postdoc in Bioengineering). He joined Peking University faculty in 2006. He is Professor in College of Engineering, and Principal Investigator and Associate Director of Biodynamic Optical Imaging Center (BIOPIC). His current research interests are single cell studies with microfluidics, label-free microscopy, and high throughput sequencing.
Quantitative single-cell analysis enables the characterization of cellular systems with a level of detail that cannot be achieved with ensemble measurement. Nonlinear optical microscopy exploits light−matter inter- actions that are intrinsic to, and often specific to, the unique optical properties of chemical compounds and structures. I will explore quantitative cellular imaging applications with nonlinear microscopy techniques, majorly the coherent Raman scattering and transient absorption. These techniques have demonstrated powerful applications in tissue imaging and in vivo diagnostics in which many cells and cell types must be interrogated in unison.
One strategy to achieve high specificity while avoiding large fluorescent molecule labels is to label proteins or cellular components of interest with small tags which have distinct vibrational signatures. Deuterium, alkyne, and azide, for example, all display a Raman peak in the “silent region” of the spectrum, a spectral region in which cells typically do not have any significant Raman peaks. With the use of small chemical tags, coherent Raman scattering offers enhanced chemical specificity with minimal perturbation of the system, which is important in many current biological research endeavors.
We also applied the transient absorption microscopy to image nanodiamonds and gold nanorods in live cells. The transient absorption signals were monitored through lock-in amplification. This provides a new way of observing nanomaterials with no need of fluorescent modification, and with no interference from background autofluorescence.