Putting Chemistry to Work for Nano- and Biomedical Research

主讲人:Prof. Younan Xia( 美国华盛顿大学 教授)

Nanomaterials are finding widespread use in diagnosis and treatment of various diseases. In this talk, I will focus on gold nanocages, a novel class of nanomaterials with hollow interiors and porous walls that can be conveniently prepared through a galvanic replacement reaction between silver nanocubes and HAuCl4 in an aqueous solution. By controlling the molar ratio of silver to HAuCl4, the localized surface plasmon resonance peaks of the resultant nanostructures can be continuously tuned from the blue (400 nm) to the near-infrared (1200 nm). These nanostructures are characterized by extraordinarily large cross-sections for absorption and scattering of light. Optical measurements indicate that the 35-nm gold nanocage has a scattering cross section of ~0.810-15 m2 and an absorption cross section of ~7.310-15 m2; both of them are more than five orders of magnitude greater than those of typical organic chromophores. Due to the photothermal effect, exposure of gold nanocages to a camera flash in air resulted in the instant melting and conversion of gold nanocages into spherical nanoparticles. Gold nanocages can be easily bioconjugated with ligands to target the receptors on specific cancer cells. Currently, we are developing this novel class of nanomaterials as both a contrast agent for optical imaging in early-stage detection of cancer and as a therapeutic agent for photothermal treatment of cancer, and as nanoscale capsules for targeted drug delivery.  
Younan Xia is the James M. McKelvey Professor for Advanced Materials in the Department of Biomedical Engineering at Washington University in St. Louis. His research interests include development of new methodologies for controlled synthesis of nanomaterials and exploration of their applications in biomedical research. He received a B.S. degree in chemical physics from the University of Science and Technology of China (USTC) in 1987 and worked as a graduate student on inorganic nonlinear optical crystals at the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences. He came to the United States in 1991, received a M.S. degree in inorganic chemistry from the University of Pennsylvania (with the late Professor Alan G. MacDiarmid) in 1993, and a Ph.D. degree in physical chemistry from Harvard University (with Professor George M. Whitesides) in 1996. He continued his training at Harvard as a postdoctoral fellow with both Professors George M. Whitesides and Mara Prentiss. He then joined the University of Washington (UW) in Seattle as an Assistant Professor of Chemistry in 1997, and was promoted to Professor in 2004. His group relocated to Washington University in St. Louis (WUSTL) in the summer of 2007. Dr. Xia has received a number of awards, including a Materials Research Society (MRS) Fellow (2009); an NIH Director's Pioneer Award (2006); a Leo Hendrik Baekeland Award from the North Jersey Section of ACS (2005); a Camille Dreyfus Teacher Scholar (2002); a David and Lucile Packard Fellow in Science and Engineering (2000); an NSF CAREER Award (2000); an Alfred P. Sloan Research Fellow (2000); an ACS Victor K. LaMer Award (1999); and a Camille and Henry Dreyfus New Faculty Award (1997). He has co-authored more than 400 publications in peer-reviewed journals and has edited a number of special issues and books on nanostructured materials and microfabrication techniques. He is an Associate Editor of the ACS journal Nano Letters, and serves on the international advisory boards of many journals, including Angewandte Chemie International Edition (2011-), Accounts of Chemical Research, Langmuir, Advanced Functional Materials, Nano Today, Nano Research, and Journal of Biomedical Optics.
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