FIP Virtual Postdoc Seminar "High- and super-resolution light-field imaging"
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Wed, 03/10/2021 - 12:00 to 13:00
Dr. Depeng Wang, BME Postdoc, Duke University
Light-field fluorescence microscopy can simultaneously record population scale activity of many individual neurons expressing genetically-encoded indicators within volumes of tissue. Conventional light-field microscopy (LFM) suffers from poor lateral resolution when using widefield illumination. Here, we report two types of LFM - light-sheet LFM (LS-LFM) and structured illumination LFM (SI-LFM) - that pattern the illumination to achieve higher spatial resolution than the resolution of conventional LFM. LS-LFM limited background contributions from sources far out of plane by exciting only a small axial range of the sample with a scanned light-sheet. Compared with conventional LFM, LS-LFM produced moderate improvements in spatial resolution, 10 times improvement in the contrast when imaging fluorescent beads, and 3.2× the signal-to-noise ratio in the detection of neural activity when imaging live zebrafish expressing a genetically encoded calcium sensor. SI-LFM obtained high resolution beyond the spatial frequency cutoffs of the light-field design by using patterned grating illumination. Such illumination excited the sample volume with grating patterns that are invariant over the axial direction. SI-LFM obtained a point-spread-function (PSF) that was approximately half the size of the conventional LFM PSF when imaging fluorescent beads. SI-LFM also resolved fine spatial features in lens tissue samples and fixed mouse retina samples, and reported neural activity with approximately 3× the signal-to-noise ratio of conventional LFM when imaging live zebrafish expressing a genetically encoded calcium sensor. Both LS-LFM and SI-LFM will facilitate the evolution of volumetric biomedical imaging of relatively transparent samples at high volumetric acquisition rates.
Depeng Wang is currently a postdoctoral associate in the Department of Biomedical Engineering at Duke University in the lab of Yiyang Gong. He obtained his Ph.D. degree from the University at Buffalo in 2018, and Master’s and Bachelor’s degrees from Nanjing University of Aeronautics and Astronautics in 2015 and 2012, respectively. His current research focuses on developing novel fluorescence microscopes that can record the activity of a large neural population with high spatial and temporal accuracy. This optical work follows his development of tomographic photoacoustic imaging during his Ph.D. study.