报告题目：Optofluidic Biolasers and Their Applications in Cells and Tissues
Andrew Ewing received his BS degree from St. Lawrence University and a PhD from Indiana University. After a postdoc at the University of North Carolina he joined the faculty at Penn State University for 25 years. He is now Professor at the University of Gothenburg and Chalmers University of Technology, Sweden, and Honorary Professor at both Nanjing University of Science and Technology and Beijing University of Science and Technology. He is a Knut and Alice Wallenberg Scholar (2011-2022), an elected member of the Royal Swedish Academy of Sciences, class 4 (chemistry), Nobel Class (2012) and the Gothenburg Academy of Arts and Sciences (2013).
Focusing on the neuronal process of exocytosis, Ewing and his group have pioneered small-volume chemical measurements at single cells, electrochemical detection for capillary electrophoresis, novel approaches for electrochemical imaging of single cells, and new electrochemical strategies to both measure release during exocytosis and the contents of individual nanometer vesicles in cells. They also pioneered the development and application of mass spectrometry imaging for subcellular and neurochemical analysis.
Ewing has recently received the Charles N Reilley Award from the Society for Electroanalytical Chemistry (2013), the American Chemical Society Award in Electrochemistry (2013), the Norblad-Ekstrand Medal of the Swedish Chemical Society (2014), the SACP Analytical Chemistry Award (2015), and the International Association of Advanced Materials European Advanced Materials Award (2017).
An electrochemical measurement of the content of nanometer transmitter vesicles combined with mass spectrometry imaging is a powerful approach . Vesicle impact electrochemical cytometry (VIEC) is a method whereby vesicles filled with electroactive metabolites impact an electrode surface, adsorb, and then are electroporated to expose their contents that are quantified by oxidation . This allows accurate determination of the contents of single nanometer neurotransmitter and hormonal vesicles and by comparison to the amount released in exocytosis, we have determined that about half the transmitter load of a large dense core vesicle is released during an exocytotic event, again experimentally demonstrating partial release. We have also developed a method, intracellular vesicle impact electrochemical cytometry (IVIEC), where a nanotip electrode is placed into a cell and the vesicles impact and open on the electrode tip allowing quantification of content .
We have used NanoSIMS imaging to spatially resolve the content across nanometer neuroendocrine vesicles in nerve-like cells to show the distribution profile of newly synthesized dopamine across individual vesicles . Furthermore, intracellular electrochemical cytometry at nanotip electrodes has been used to count the number of molecules in individual vesicles and to compare to the amount imaged in vesicles. This allows us to add a novel quantitative aspect to the mass spectrometry imaging experiment. These nanoanalytical tools quantitatively reveal that dopamine loading/unloading between vesicular compartments, dense core and halo solution, is a kinetically limited process.
Using IVIEC, we have discovered that a chemotherapeautic drug that decreases cognition, cisplatin, changes exocytosis, but not vesicle content . We have discovered that the learning supplement, zinc ion, decreases vesicle content, but not exocytosis by changing the fraction that is released . We have examined the effects of lidocaine, barbiturate, and nocodazole and found that all the drugs mentioned here act via changing the partial opening of the pore during exocytosis and the fraction of transmitter released seems to be a key aspect for plasticity. Finally, intracellular cytometry has been used to measure the content of small synaptic vesicles (50-60 nm) in the fruit fly nerve terminals and the fraction released is only 5-20 %.
 N.T.N. Phan, X. Li, A.G. Ewing, “Measuring synaptic vesicles using cellular electrochemistry and nanoscale molecular imaging,” Nature Reviews Chemistry, 1, 2017, DOI:10.1038/s41570-017-0048.
 J. Dunevall, H. Fathali, N. Najafinobar, J. Lovric, J. Wigström, A-S. Cans, A.G. Ewing, “Characterizing the catecholamine content of single mammalian vesicles by collision–adsorption events at an electrode,” J. Am. Chem. Soc. 137, 2015, 4344-4346.
 X. Li, S. Majdi, J. Dunevall, H. Fathali, A. G. Ewing, “Quantitative measurements of transmitters in vesicles one at a time in single cell cytoplasm with nano-tip electrodes,” Angewandte Chemie Int Ed., 54, 2015, 11978-11982.
 J. Lovrić, J. Dunevall, A. Larsson, L. Ren, S. Andersson, A. Meibom, P. Malmberg, M.E. Kurczy, A.G. Ewing, “Nano secondary ion mass spectrometry imaging of dopamine distribution across nanometer vesicles,” ACS Nano 11, 2017, 3446-3455.
 X. Li, J. Dunevall, A. G. Ewing, “Single cell amperometry reveals cisplatin treatment modulates the release of catecholamine transmitters during exocytosis,” Angewandte chemie, 55, 2016, 9041-9044.
 L. Ren, M.D. Pour, S. Majdi, X. Li, P. Malmberg, A.G. Ewing, “Zinc regulates chemical transmitter storage in nanometer vesicles and exocytosis dynamics measured by amperometry,” Angew Chem Int Ed, 56, 2017, 4971-4975.
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