Topic：The application of focused ion beam in 3D reconstruction and milling in situ for biological sample

Speaker：Dr. Xiaomin Li

Host：Prof. Zhongmin Liu

Time：June 19, 10:00 - 11:30 am

Venue：Lynn Library Lecture Hall 111

Abstract:

The integration of focused ion beam (FIB) with scanning electron microscopy (SEM) has emerged as a transformative tool for biological research. Serial block-face scanning electron microscopy (SBF-SEM) enables automated high-resolution imaging and 3D reconstruction of cellular ultrastructure, where critical factors such as sample preparation, E-beam and I-beam parameters significantly determine the quality and throughput of serial image acquisition. To enhance target localization precision, we established a correlative workflow combining fluorescence microscopy with SBF-SEM. Furthermore, cryo-focused ion beam (cryo-FIB) milling was applied to produce 100- 200 nm- thin lamellae from vitrified cells and tissues. Through systematic comparisons of dual-beam instruments, we developed standardized protocols for cryo-FIB milling. These protocols have been formalized into a Laboratory Standard Operating Procedure (L-SOP) to ensure reproducibility. Additionally, we highlight the integration of fluorescence imaging with milling and cryo-electron tomography (cryo-ET) data acquisition, achieving in vivo molecular localization. These integrated approaches demonstrate how FIB-SEM technologies can advance structural biology in situ from nanometer-scale reconstruction to functional studies.

Brief introduction of the speaker: 

Dr. Xiaomin Li holds a Ph.D. in Biophysics from the Institute of Biophysics, Chinese Academy of Sciences, and currently serves as a senior engineer and core member of the core facility of Life Sciences at Tsinghua University. She pioneered the establishment of a correlative light-electron microscopy (CLEM) and in situ structural biology research system at Tsinghua’s cryo-EM facility, providing critical technical support for key projects and high-impact research. With over 10 SCI publications (including first-author papers), 3 authorized patents, and contributions to a textbook, Dr. Xiaomin Li has demonstrated strong academic output. As a key member in one National Key R&D Program and one Beijing Municipal Science & Technology Project, she also leads several Tsinghua Experimental Technology Innovation Funds (including key projects). Her honors include the Outstanding Technical Talent award from the National Facility for Protein Science (Beijing), Tsinghua University Experimental Technology Achievement Award, and Life Sciences School Outstanding Staff recognition.