Low-coherence Biophotonics Imaging for the Brain
Abstract
This talk will highlight our recent efforts in exploring the brain using low-coherence light. We will discuss two scenarios: intraoperative assessment of brain cancer infiltration in patients and real-time imaging of dynamic neural activities in freely behaving rodents. In the first scenario (clinical translation), we developed a color-coded quantitative optical coherence tomography (qOCT) technology, providing neurosurgeons with direct visual cues for maximizing cancer resection while minimizing damage to healthy brain tissue. Our results from over 50 patients demonstrate excellent specificity and sensitivity (>95%). For the second scenario (basic research), we created the first all-fiber-optic, head-mounted, ultracompact (~2 mm diameter), and ultralight (<1 g) two-photon fiberscopy platform, allowing for high-resolution imaging of neuronal activity in freely walking/rotating mice. Recent advancements enable a 15X increase in the area field of view and a 10-30X increase in imaging frame rates. Detailed neural imaging results will be presented at the seminar. If time permits, other applications of these technologies for noninvasive in vivo optical histology will also be discussed.
One significant finding is that lipid turnover decreases faster in aged female Drosophila compared to males. Additionally, dietary restrictions, downregulation of the insulin/IGF-1 signaling (IIS) pathway, and AMPK activation significantly alter lipid metabolism in aged or Alzheimer’s-affected brains. The introduction of APoD and PRM algorithms has enhanced our current multimodal metabolic nanoscopy to deliver superresolution with hyperspectral volumetric imaging capabilities. By using deuterated molecules—including glucose, amino acids, fatty acids, and water molecules—as bioorthogonal probes, this technology provides insights into the metabolic heterogeneity of organs such as the brain, adipose tissue, liver, muscle, retina, and kidneys.
Biography
Xingde Li earned his PhD in Physics from the Univ. of PENN in 1998. Following 3 years of postdoctoral training at MIT, he began his academic career at the University of Washington. In 2009, he joined the BME Department at Johns Hopkins as Associate Professor and later became a Full Professor in 2011. His research focuses on biophotonics imaging technologies and their applications in translational and basic research. Beyond research endeavors, he has actively participated in various committees for different societies, chaired numerous international conferences, and served on many proposal review panels. He has also taken on editorial roles as a topical editor, associate editor for several journals and the lead founding EiC for a Science Partner Journal – BMEF. He has been elected Fellow of OPTICA, SPIE, and AIMBE.
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