题 目：Small Electrochemical Sensors and Single Cells: Zeptomoles Milliseconds and the Nature of Reality in Exocytosis
报告人：Prof. Andrew Ewing
Chalmers University of Technology and University of Gothenburg
地 点：南京大学-约翰斯•霍普金斯大学中美文化研究中心 匡亚明报告厅
时 间：2015年4月24日（星期五）上午10:00 摘要：
Electrochemical methods provide a powerful approach to investigate neurotransmitter release and storage from and in single cells. Additionally, the fly model (Drosophila melanogaster) provides a unique system to examine neurotransmitter release and drug dependence mechanisms in a small, but complete system.
Electrochemical cytometry can be used to separate nanometer vesicles, lyse them on an electrode surface, and amperometrically detect the active contents of each vesicle in a high throughput manner. We began with a hybrid capillary-microfluidic device surrounding the electrode to rapidly determine levels of aminergic transmitters in vesicles. More recently, we have developed a new method of electrochemical cytometry to measure the total content of single neurotransmitter vesicles. The electrochemical response to single adrenal chromaffin vesicles filled with hormone transmitters as they impact a 33-um diameter disk-shaped carbon electrode will be shown. The vesicles appear to adsorb onto the electrode surface and sequentially spread out over the electrode surface trapping their contents against the electrode. These contents are then oxidized and a peak results for each vesicle that bursts. A large number of current transients can be observed if the concentration of vesicles is high relative to the area of the electrode. We have also been able to accomplish this type of cytometry in the cytoplasm of living PC12 and adrenal cells. Comparison of the contents of these biological vesicles to the release of catecholamine from single cells supports the concept that only a fraction of transmitter is released during exocytosis.
We have also used amperometry to examine post-spike feet that would be expected if the fusion pore was closing again with open and closed exocytosis and to examine exocytotic release at varicosities in the fly larvae. We conclude that normal exocytosis is open and closed! In addition, the use of lipids to alter exocytosis has been shown opening a new avenue for pharmaceutical targets. Thus, we have used imaging mass spectrometry to examine the levels of phospholipids needed to change to alter the rate of exocytosis. We think this is a potential mechanism for short-term memory formation. 报告人简介：
Andrew Ewing现任瑞典哥德堡大学（University of Gothenburg）教授。于1983年在美国印第安纳大学（Indiana University）取得博士学位，师从R. Mark Wightman教授；1983-1984年在北卡大学教堂山分校Royce W. Murray教授组做博士后研究。1984-2010年，在宾州州立大学任助理教授、副教授、教授、J. Lloyd Huck讲席教授等职。2010年起任University of Gothenburg教授。2011年起双聘为University of Gothenburg和Chalmers University of Technology教授，并任Joint Chalmers-GU Initiative for Bioanalytical Chemistry主任。
研究领域涉及单细胞分析、神经分析化学、化学和电化学成像方法、质谱等。在《Science》、《Nature Medicine》、《PNAS》、《JACS》、《Angew. Chem.》等杂志发表论文290余篇，被引用 14000余次，H-index为66。
Ewing教授在分析化学领域取得杰出的成就，获得了众多奖项和荣誉，包括the Pittcon Award in Analytical Chemistry (2015), Norblad-Ekstrand Medal of the Swedish Chemical Society (2014), ACS Analytical Division Award in Electrochemistry (2013), Charles N Reilley Award in Electroanalytical Chemistry (2013)，European Union Marie Curie Chair (2007-2010)，Alfred P. Sloan Research Fellowship (1989)，NSF Presidential Young Investigator Award (1987)等。
Ewing教授于2004年当选美国科学促进会会士，于2009年当选英国皇家化学会会士，于2012年当选瑞典科学院院士。目前担任《Analytical Chemistry》副主编。
欢迎参加！
生命分析化学国家重点实验室
现代工程与应用科学学院 | 