【校庆115周年活动预告】Optical Imaging of Nanoscale Chemical and Biological Processes
方宁，美国佐治亚州立大学副教授。厦门大学本科毕业，在加拿大英属哥伦比亚大学（UBC）获得硕士和博士学位，在美国能源部衣阿华州立大学和艾莫斯实验室从事过博后研究。获得过Journal of Analytical and Bioanalytical Chemistry的年度最佳论文奖和分析化学与光谱学学会联合会的创新奖。在Nature Communications、JACS、Angewandte、ACS Nano、Nano Letter、Analytic Chemistry等期刊发表重要论文约20篇。目前的研究兴趣主要是通过开发和使用新颖的光学成像平台获得新的化学和生物学发现，这些平台可以为单分子和纳米颗粒提供亚衍射极限空间分辨率、高角度分辨率、优越检测能力和纳米级别的定位精度。
• Rotational Tracking: The knowledge of rotational dynamics in and on live cells remains highly limited due to technical limitations. The differential interference contrast (DIC) microscopy-based Single Particle Orientation and Rotational Tracking (SPORT) techniques have been developed in the Fang Laboratory to acquire accurate measurements of anisotropic plasmonic gold nanorods in complex cellular environments. Rich information in five dimensions, including the x, y, z coordinates and the two orientation angles (azimuthal angle and polar angle , as defined in the figure) of the probe’s transition dipole, can be obtained from SPORT experiments. The SPORT technique is capable of extracting important information (including rotational rates, modes, and directions) on the characteristic rotational dynamics involved in cellular processes, such as adhesion, endocytosis, and transport of functionalized nanoparticles, as may be relevant to drug delivery and viral entry.
• Single Molecule Catalysis: The emergence of single molecule-based super-localization and super-resolution microscopy imaging techniques have dramatically improved our ability to reveal more detailed molecular dynamics and structural information and led to new discoveries in chemical and biological research that were previously unattainable with conventional diffraction-limited techniques. However, the current super-resolution chemical imaging techniques still lack several critical abilities, including insufficient axial resolution and the difficulty of imaging more complex three-dimensional (3D) nanomaterials. In seeking to circumvent these limitations, we are developing 3D super-resolution imaging for understanding molecular dynamics (including diffusion, adsorption, and chemical conversion, as well as their coupling) in nanopores at the single-molecule level under operando conditions. Highly tunable core-shell structures with well-defined geometry and manageable complexity have been designed and synthesized, and then visualized under our optical imaging system. Single molecule trajectories with nanometer resolution have been acquired to elucidate the effects of pore size, length, orientation, and surface ligands on molecular transport. New experimental insights on transport in nanoscale confinement acquired with the model core-shell porous structures can be generalized to guide the development of porous materials for heterogeneous catalysis and analytical separations.