BME PhD Defense Announcement for Li Fang (Fang Huang, advisor)
Everyone is invited to attend the public presentation beginning at 3:00 PM.
Title: Aberration analysis and high-density localization for live-cell super-resolution imaging
Date: May 22th
Time: 3:00 PM
Location: MJIS 2001 and Zoom
Committee: Dr. Fang Huang (Chair), Dr. Young L. Kim, Dr. Leopold N. Green, Dr. Chongli Yuan
Abstract: Single molecule localization microscopy (SMLM) has become an essential tool in imaging nanoscale biological structures. It breaks the diffraction limit by utilizing photo-switchable or photo-convertible fluorophores to obtain isolated single molecule
emission patterns (i.e. PSFs) and subsequently localize the molecule’s position with a precision down to ~ 20 to 80 nm laterally-axially. However, optical aberrations compromise its spatial resolution. Additionally, conventional SMLM algorithms require sparse
activation to reduce emission pattern overlap, which restricts imaging speed and temporal resolution, thus limiting its utility in dynamic live cell imaging. In this study, we first conducted a comprehensive quantitative analysis of the theoretical precision
limits for position and wavefront distortion measurements in the presence of aberrations, which enhances our understanding of aberration effects in SMLM and lays the groundwork for developing more effective aberration correction methods. To improve temporal
resolution, we developed a high-density single molecule localization algorithm that utilizes deep learning to analyze molecule blinking sequences. This approach allows us to achieve high localization precision and resolve structures at tens of nanometers resolution,
even with highly overlapped blinking data. Validated by both simulated and high-density experimental data, our algorithm successfully resolves the complex structures of various cellular organelles and captures rapid dynamic movements in live cells. This work
addresses the knowledge gap about aberrations in SMLM and expands its applications to more dynamic and detailed studies of cellular processes.