题目：Turning the tide on Upconversion Cross-relaxation

时间：2019年4月2日（周二）上午10点

地点：南区物理与光电工程学院1110

报告人：Timothy Tan 副教授（南洋理工大学）

报告摘要：Cross-relaxation in lanthanide nanoparticles has always been deemed deleterious in upconversion emissions, especially so for lanthanide ions with multiple energy states. Such ions, when placed within close proximity, encourage cross relaxation energy transfer leading to loss in upconversion quantum yield. In this talk, I will show that cross-relaxation may not always be undesirable in upconversion processes. First of all, I will provide insights on the understanding of cross-relaxation processes, and through this understanding, we turn the tide around and exploit cross-relaxation for tuning single upconversion emission (1). Through this understanding, we also learn how to overcome its deleterious effects through a nanostructuring technique and achieve 808 nm near-infrared activated photodynamic therapy (2). Finally, I will showcase putting cross-relaxation into good use in one of the highest photothermal efficiency attained in tumor photothermal therapy with simultaneously photoacoustic imaging (3).

报告人简历：Dr Timothy Tan obtained his Ph.D in Chemical Engineering in 2004 from the University of New South Wales, Australia. He is currently an Associate Professor in the School of Chemical and Biomedical Engineering and Deputy Director of CNYang Scholar Program of Nanyang Technological University, Singapore. He is interested in the engineering, manipulation and interrogation of nano-biophoto systems, with an ultimate goal of enhancing biological and chemical functions. He has filed 5 patents with 2 of them granted, edited a book, published 4 book chapters and more than 90 original papers. His recent awards include Public Administration Award 2015 by the President of Singapore and Young Investigator Award in “International Symposium of Materials on Regenerative Medicine 2012”. Focusing on nano- and photon-driven biomedical engineering, his group has developed ultrasmall, superbright upconversion nanomaterials suitable for skin photomedicine since they are non-phototoxic and non-cytotoxic, with potential application in eczema and carcinoma phototherapy as well as wound healing. His group has also developed an electrostatic tunable hydrogel which has demonstrated very effective siRNA delivery and induced gene knockdown in glaucoma models. He is currently seeking clinical collaboration to conduct further studies and validation towards commercialization.