Basic Information
Abstract Number: 210-1    
Author Name: Ning Fang Affiliation: Iowa State University
Session Title: Microscopy: New Instrumental Techniques
Event Type: Oral
Event Title: Investigations of Translational and Rotational Motions in Living Cells Using Plasmonic Nanoprobes and Differential Interference Contrast Microscopy
Presider(s): Ma, Yinfa Start Time: 01:00 PM ( Slot # 1 )
Date: Sunday, February 28th, 2010 Location: 206B
Keywords: Biological Samples, Biotechnology, Imaging, Microscopy

Sun, WeiIowa State University
Wang, GufengIowa State University

Abstract Content
Characteristic translational and rotational motions of biomolecules and nanoparticles are fundamental to most chemical and biological phenomena. Translational motion can be readily revealed by a variety of single-particle/molecule tracking methods. However, rotational motion is much more difficult to resolve due to technical limitations. The prominent examples of lacking knowledge on rotational motion are endocytosis and intracellular transport in live cells. The current understanding of rotational motion was acquired mostly in vitro using methods based either on fluorescence polarization or on super-localization of translational probes. Resolving dynamic rotational motion in living cells or other complex environments is still challenging.

We developed a novel optical imaging tool, based on plasmonic nanoparticle probes and differential interference contrast (DIC) microscopy, to visualize and decipher single-nanoparticle/molecule translational and rotational motion in complex environments and address outstanding questions in chemical and biological systems that were previously unattainable. For example, gold nanorods have anisotropic plasmon-resonant absorption and scattering in the visible and near-infrared regions, making them attractive orientation probes in optical microscopy. DIC microscopy is known for providing excellent contrast in non-intrusive direct observations of biological processes. Their marriage, upon several significant improvements on instrumentation, leads to a new imaging technique with important advantages over any existing method for resolving single-nanoparticle/molecule rotational motion. We used this high-speed live-cell imaging tool to decipher rotational motions of single gold nanorods in unprecedented detail during receptor-mediated endocytosis by A549 human lung cancer cells and subsequent intracellular transport on the microtubule network.