很高兴邀请到香港中文大学的王建方教授和美国Lawrence Berkeley National Lab的

Paul Ashby研究员来我所访问并作学术报告。学术报告时间是5月6日，本周五早上

9－11点， 地点A718，请大家踊跃参加。

学术报告一：Plasmonic Gold Nanocrystals and Related Nanostructures

Jianfang Wang

Department of Physics, The Chinese University of Hong Kong

Abstract:  The localized plasmon resonances of noble metal nanocrystals

have found applications in a wide range of areas, such as imaging,

sensing, nanomedicine (photothermal therapy and controlled drug delivery),

enhancement of linear and nonlinear optical signals (Raman, fluorescence,

high-harmonic, solar energy harvesting, two-photon excitation,

photolithography, and upconversion), optics and optoelectronics

(subwavelength waveguiding, photoswitching, optical data storage, spasers,

optical tweezers, and metamaterials), and catalysis. Gold nanocrystals are

chemically stable, biologically compatible, and exhibit extraordinary

plasmonic properties. I will describe our synthetic control of the

plasmonic properties of gold nanocrystals, construction of gold

nanocrystal-based hybrid nanostructures containing semiconductors or other

metals. I will also describe our work on the interactions between the

localized plasmon resonances and the fluorescence process.

学术报告二：Toward Capturing Membrane Protein Dynamics with the Fiber

Force Probe

Paul Ashby 简介：Paul Ashby started his scientific career at Westmont

College in California by majoring in chemistry. Subsequently, he went to

Harvard and joined the group of Charlie Lieber. There he investigated

intermolecular and surface forces by developing new techniques such as

Brownian Force Profile Reconstruction and Energy Dissipation Chemical

Force Microscopy. He then went to the Molecular Foundry at Lawrence

Berkeley National Lab where, as a postdoc, he continued to probe a variety

of interfacial chemistry and mechanical properties such as the atmospheric

chemistry of sea salt aerosols and the influence of extracellular matrix

elasticity on tissue vitality. Since becoming a staff scientist at the

Molecular Foundry he has worked to understand membrane protein function by

imaging the cell surface with high resolution. Today he will share his

efforts Towards Capturing Membrane Protein Dynamics with the Fiber Force

Probe.

Abstract： Living cells readily deform under the minimum force required to

perform an AFM measurement precluding the imaging of membrane protein

complexes.  Attempts to use feedback methods such as Q-control have failed

to improve the image quality. I will discuss why Q-control does not

provide an advantage for imaging in solution.1  Instead, the thermal

force-noise of the cantilever is the principal limitation to reducing

sample deformation.  Minimizing a cantilever's cross- section reduces its

noise significantly and the minimum size of the cantilever is currently

limited by a conventional deflection detection scheme, which requires a

large surface area for laser specular reflection. I will present an

optical deflection detection technique enabling the use of nanowires as

cantilevers and show that we achieve a force noise in water that is orders

of magnitude gentler than conventional AFM. This is a significant

milestone towards non-invasive scanning probe imaging of biological

processes on the surfaces of vesicles and cell membranes.2 Lastly, I will

discuss our use of alternative scan algorithms and data processing for

high-speed imaging and the capture of protein dynamics.