Events Calendar

Imaging Seminar - Junjie Yao, Friday, March 25th at 2:00pm in EEB 132

Speaker: Junjie Yao, Washington University in St. Louis, Missouri

Talk Title: Photoacoustic Imaging beyond Traditional Limits

Abstract: By physically combining electromagnetic and ultrasonic waves, photoacoustic imaging (PAI) has proven powerful for multi-scale anatomical, functional, and molecular imaging. In PAI, a short-pulsed laser beam illuminates the biological tissue to generate a small but rapid temperature rise, which leads to emission of ultrasonic waves due to thermoelastic expansion. The high-frequency ultrasonic waves are detected outside the tissue by an ultrasonic transducer to form an image that maps the original optical energy deposition in the tissue. PAI seamlessly combines the rich optical absorption contrast of biological tissue with the high optically- or acoustically-determined spatial resolutions.

My talk will focus on three recent advances of PAI on exciting new fronts. First, PAI has broken the optical-diffraction limit and achieved super-resolution (~80 nm) imaging by using non-linear photobleaching or photo-switching dynamics, extending its applications into sub-cellular nano-dimensions. Second, by using a novel pulse-width-based single-wavelength method, ultra-fast photoacoustic microscopy has achieved a 1D oxygenation imaging rate of 100 kHz, allowing label-free imaging of mouse brain activity with high spatial-temporal resolution. Third, taking advantage of the newly developed near-infrared non-fluorescent phytochrome BphP1, which can be reversibly switched on and off, PAI has achieved more than 200 times enhancement in detection sensitivity in reporter gene imaging, allowing early-stage cancer imaging at ~10 mm in tissue with a detection sensitivity of ~20 cancer cells.

Biography: Dr. Junjie Yao received his B.E. and M.E. degrees in Biomedical Engineering from Tsinghua University, Beijing, in 2006 and 2008, respectively. He received his Ph.D. degree in Biomedical Engineering at Washington University, St. Louis (WUSTL), in 2013. He is currently a postdoctoral research associate at WUSTL.

Dr. Junjie Yao's research interest is in photoacoustic imaging technologies in life sciences, especially in functional brain imaging and early cancer detection. Dr. Yao has published more than 60 articles in peer-reviewed journals such as Nature Methods, Nature Medicine, PNAS, and PRL. These publications have received more than 1650 world-wide citations in the last five years. He (co-)invented photoacoustic Doppler-bandwidth flowmetry, photoacoustic oxygen metabolic microscopy, photo-imprint super-resolution photoacoustic microscopy, and reversibly-switchable photoacoustic tomography. Dr. Yao's future research will center on developing novel photoacoustic technologies and translating the laboratory imaging advances into diagnostic and therapeutic applications for a broad range of diseases, especially brain disorders and cancers.

Host: EE-Electrophysics

Location: Hughes Aircraft Electrical Engineering Center (EEB) - 132

Audiences: Everyone Is Invited

Contact: Marilyn Poplawski