| Speaker : |
・Dr. Vincent Senez (CNRS/IEMN, Lille, France)
・Dr. Taher Saif (University of Illinois at Urbana-Champaign, Illinois, USA) |
| Subject : |
21st Century COE Mechanical Systems Innovation Open Seminar (IIS NonoBio Seminar/Foreign Researchers Seminar) |
| Date : |
May 15, 2006 2:00pm-4:00pm (Conference room 1, Institute of Industrial Science, Komaba campus) |
| Outline : |
2:00pm-3:00pm
Ultra Wide Band Dielectric Spectroscopy of Single Cell in Microfluidic Devices
Speaker: Dr. Vincent Senez (CNRS/IEMN, Lille, France)
Single-cell analysis is a very important field of research. Currently, the prevailing paradigm to analyze cellular functions is the study of biochemical interactions using fluorescence based imaging systems. However, the elimination of the labelling process is highly desirable to improve the accuracy of the analysis. Recent developments in micro- and nanofabrication technologies are offering great opportunities for the analysis of single cells; the combination of micro fluidic environments, nano electrodes/wires and ultra wide band electromagnetic engineering will soon make possible the investigation of local (submicrometer scale) dynamic processes integrating several events at different time scales. We present our work which aim at investigating single-cells with the help of MEMS and NEMS (Micro and Nano Electro Mechanical Systems) and ultra wide band (DC-THz) electromagnetic characterization techniques.
3:00pm-4:00pm
Microinstruments for Studying Metals and Single Cells at Submicron Scale
Speaker: Dr. Taher Saif (University of Illinois at Urbana-Champaign, Illinois, USA)
We will discuss two novel micro force sensors that are used to study mechanical behavior of nano scale free standing metal films in-situ in transmission electron microscope (TEM) and single living cells. We show that mechanical behavior of ductile metals, such as aluminum, at nano scale (thickness and grain size) is dramatically different from their macroscopic counterpart. Mechanistic interpretations for such behavior will be discussed based on in-situ TEM observations. Single living cells, under large stretch, show strong linearity and reversibility, contrary to general expectation. Under compression and indentation, however, the force response is plastic, irreversible and hysteretic. In-situ visualization of actin network during force response measurements reveals the corresponding mechanism for irreversibility. Under indentation, actin network remodels - it depolymerizes at discrete locations and forms actin agglomerates all over the cell irreversibly, possibly due to cell signaling. Similar actin agglomeration is found in various biological processes such as during ischemic attack. This is the first evidence of actin agglomeration due to mechanical stimuli. |
|
|
