题 目：Applications of Ultrafast Laser Microsurgery and Live Tissue Imaging in Biomedical Research
报告人：Jun Cheng (University of Illinois at Chicago, USA)
Ever since their invention, laser and optical imaging microscopy have revolutionized biomedical research. Ultrafast laser pulses to selectively ablate structures with nanometer precision has found enormous applications, such as 3D micromachining in material processing and structural-knockout in biomedical fields. Live tissue imaging makes it possible to directly study kinetics and biomechanical properties of subcellular structures within their intact microenvironment.
Besides protein patterning by ultrafast laser irradiation, two projects are discussed in details to demonstrate the efficacy and value of ultrafast laser microsurgery in selectively ablating intracellular structures. One project is to study bio-mechanistic oscillatory movements of mitotic chromosomes (known as “directional instability”), in which sections of a chromosome’s arms were removed by femtosecond laser microsurgery thus decreasing the polar-ejection force on the chromosome. The second project is to investigate study the role of ASC protein aggregation during apoptosis by their structural knockouts, which is complimentary to genetic knockout method.
In many tissue types, stem cells reside inside their microenvironment and divide asymmetrically, i.e, one daughter cell self-renews and the other daughter cell differentiates. Using male Drosophila gonad as a model system, 3D live tissue imaging microscopy was developed to directly study the kinetics and biomechanics of subcellular structures during asymmetric stem cell divisions. The results show that aged germ stem cells uniquely re-orient their centrosomes before undergoing asymmetric stem cell divisions, and cyst stem cells adopt the distinctive spindle repositioning mechanism to achieve asymmetric stem cell divisions.
• 2010年-现在， 美国伊利诺斯大学芝加哥分校生物工程系，助理教授