讲座题目：Skin in the Game：Photoproperties of DNA and Melanin Biopolymers Revealed by Ultrafast Laser Spectroscopy 主讲人：Bern Kohler 教授 主持人：陈缙泉 研究员 开始时间：2019-05-16 10:00:00 讲座地址：中北校区理科大楼A814 主办单位：精密光谱科学与技术国家重点实验室
报告人简介： Appointments July 2016 – present Professor and Ohio Eminent Scholar, Department of Chemistry and Biochemistry, The Ohio State University 2009 – 2016 Professor of Chemistry, Montana State University 2011 – 2012 Interim Department Head, Department of Chemistry and Biochemistry,Montana State University Summer 2008 Visiting Professor of Physics, Aarhus University 1995 – 2009 Assistant, Associate, Full Professor, Department of Chemistry, The Ohio State University Education B.S. 1985 Chemistry Stanford University Ph.D. 1990 Physical Chemistry Massachusetts Institute of Technology Advisor: Prof. Keith A. Nelson Thesis: Ultrafast Dynamics of Molecular Liquids Investigated by Femtosecond Light Scattering Honors and Awards Inter-American Photochemical Society (I-APS) Award in Photochemistry, 2017. AAAS Fellow, 2015. Cox Award for Creative Scholarship and Teaching, MSU, 2015. Charles and Nora L. Wiley Faculty Award for Meritorious Research, Montana State University, 2010. Arts and Sciences Outstanding Teaching Award Finalist, The Ohio State University, 2009. Visiting Professor Fellowship, University of Aarhus, Denmark, summer 2008. Research Fellow of the Alexander von Humboldt Foundation, 2004-2005. Associate Editor, Photochemistry and Photobiology, 2004-present. Research Interests Ultrafast excited state dynamics in biomolecules (DNA, melanin) and nanomaterials; electronic and vibrational spectroscopy in the condensed phase; Exciton and charge transport dynamics in selfassembled nanomaterials for photocatalysis and solar energy conversion 报告内容： An Achilles heel of many organic materials is photochemical degradation, yet living organisms have thrived for eons in a world bathed in UV and visible radiation. Biopolymers, with their long history of evolutionary optimization, can inspire new strategies for designing photoactive materials. Our bottom-up studies of DNA excited states began twenty years ago with single nucleotides and have progressed to experiments on single- and double-stranded oligonucleotides. Nucleobase monomers behave as absorbing sunscreens with excited states that decay in less than 1 ps. UV excitation of single strands creates self-trapped excitons whenever two or more nucleobases are stacked. In double-stranded DNA, femtosecond time-resolved IR spectroscopy reveals photoinduced interstrand proton transfer. Growing understanding of DNA photophysics is now being used to study self-assembled DNA-metal nanoassemblies. In human skin, the biopolymer melanin is present as carbonaceous nanoparticles, but melanin is found throughout the kingdom of life. Paramagnetic melanin is not just photoprotective, but may act as a scavenger of radicals. The structure of melanin is unknown, impeding efforts to understand this multifunctional material. The structureless absorption spectrum of this black pigment is believed to result from a heterogeneous distribution of chromophores. Our latest experiments demonstrate selective bleaching of groups of chromophores, but reveal a wavelength-independent response. Striking similarities between the photoproperties of melanin and disordered, two-dimensional carbon nanomaterials will be discussed. |
