报告题目：Time resolved imaging of biological process at the nanoscale – From molecular self-assembly to bacterial cell division

报 告 人：Prof. Georg E. Fantner, EPFL

时        间：2019 年 9月 9日（周一）上午 10: 00，

地    点：南楼二层会议室

邀 请 人：裘晓辉 研究员

Abstract: “Change is a fundamental fact of life”. As such, in order to understand living systems, it is essential to characterize their changes over time. This is a challenging task, especially at the nanometer scale. Most nanometer scale microscopy methods work in conditions that are not biocompatible, which makes nanoscale imaging of biological processes difficult. The atomic force microscope (AFM) offers the opportunity to image biological specimens in their close to native environment while still maintaining nanometer resolution. However, time resolved AFM imaging is limited by fundamental and technical limitations. These limitations are both on the short time scale (how many images can be taken in a given period, e.g. the temporal resolution) as well as in the long timescale (how long can an AFM imaging experiment be continuously maintained, e.g. the maximum experimental duration). In this talk I will discuss our recent advances in extending the temporal resolution of AFM as well as the maximum experimental duration. I will present examples of new biological discoveries we obtained using this extended time
window.
As a first example I will show the self-assembly process of the centriolar protein SAS-6 into rings, which is at is at the heart of the assembly of the mitotic spindle. Using a new imaging mode, photothermal off resonance tapping (PORT), we were able to image the assembly of the SAS-6 proteins rings one molecule at a time and derive reaction kinetics from these single molecule observations [1]. The second example is the growth and division of Mycobacterium Smegmatis, a model system for the study of tuberculosis. Using long-term, time-lapse AFM imaging we were able to describe how the bacteria control their cell division in time and space [2,3]

References:
[1] High-speed photothermal off-resonance atomic force microscopy reveals assembly routes of centriolar scaffold protein SAS-6, A.P. Nievergelt, N. Banterle, S. H. Andany, Pierre G？nczy and G.E. Fantner, Nature Nanotechnology, 13, 696-701.
[2] Division site selection linked to inherited cell surface wave troughs in mycobacteria H.-A. Eskandarian, P.D. Odermatt, JXY. Ven, M.T.M. Hannebelle, A.P. Nievergelt, N. Dhar, J.D. McKinney & G.E. Fantner, Nature Microbiology, volume 2, Article number: 17094 (2017) DOI: 10.1038/nmicrobiol.2017.94
[3] Overlapping and essential roles for molecular and mechanical mechanisms in mycobacterial cell division, PD. Odermatt 1, M.T.M. Hannebelle, H. A. Eskandarian, A.P. Nievergelt, J.D. McKinney, and G. E. Fantner, Nature Physics (in press) (2019)

Biography：GEORG E. FANTNER received his MS degree from the University of Technology Graz in 2003, and his PhD degree from UC Santa Barbara in 2006 (advisor: Paul K. Hansma). During his masters and PhD, he developed a number of high performance AFM instruments and applied them to the study of the molecular origin of bone fracture toughness. After a Postdoc in the biomolecular materials lab at the Massachusetts Institute of Technology (advisor: Angela M. Belcher), he joined the école Polytechnique Fédéral de Lausanne as assistant professor in 2010. Now, as associate professor, he leads the laboratory for bio- and nano-instrumentation in the institute for bioengineering. His research, which has been funded by the European Research Council with an ERC starting grant and an ERC consolidator grant, focusses on the development of new technologies to measure and manipulate nanoscale structures in general, and the development of atomic force microscopy instrumentation in particular. He applies these instruments to answer questions in a variety of fields ranging from materials science and nanotechnology to biology and life science. His interdisciplinary work has been published in many high impact journals such as Nature Materials, Nature Nanotechnology, Nature Cell biology, Nature Microbiology, Nature Communications, Nano Letters, and Science, as well as featured in a number of popular science- and general-interest magazines. He serves as scanning probe microscopy editor for Microscopy and Microanalysis (CambridgeCore), and as editorial board member for Scientific Reports. His recent work focusses on the development of time resolved AFM imaging, encompassing new modes for high-speed AFM imaging of molecular processes, as well as long-term time lapse imaging of cellular processes. Prof. Fantner hold several patents in the field of nanotechnology and is the co-founder of two nanotechnology companies. Recently he has become active in the field of open hardware, where he explores new avenues to foster free academic exchange of knowledge, particularly for the development of highly sophisticated custom instruments.