Watt W. Webb

<TITLE>Watt W. Webb</TITLE> <CENTER><TABLE BORDER=0 ALIGN=CENTER VALIGN=TOP CELLPADDING=10> <TR> <TD VALIGN=TOP><table border=3 cellpadding=1><tr><td><IMG Align=TOP SRC="wwebnew.jpg" ></td></tr></table></TD> <TD VALIGN=MIDDLE><B><H2><CENTER>Watt W. Webb</CENTER></H2><HR> <H3>Professor of Applied and Engineering Physics<BR> <A HREF="http://www.engr.cornell.edu/aep/AEP.html">Applied and Engineering Physics</A><BR> 223 Clark Hall<BR> Cornell University</H3></TD> </TR> </TABLE> </CENTER> <HR> <BR> <BR><strong>Research Interests</strong><br><br> The aim of our research in biological physics is to understand, at the molecular level, the dynamics of basic biophysical processes. It is a continual challenge to detect the exquisite subtlety of molecular signals and to broaden the paradigms of physical science to encompass biological complexity. <P><I> Biophysics.</I> We study the dynamics of biophysical processes in living cells using modern physical optics. Molecular diffusion on membranes, and interactions of receptors with their ligands and with the cytoskeleton, underlie immunological and hormonal responses and transmembrane signals in the brain. We utilize digital image-processing techniques to track individual molecular receptors in motion on the surfaces of living human cells. The fluctuating electrical conduction through single molecular channels of nerve membranes are recorded at the picoampere level to observe mechanisms of responses to neurotransmitters and drugs and sensory signals. <P> <I>Physical Instrumentation.</I> The need for probes that are sensitive to the dynamics of a few molecules at the pace of cellular processes continually pushes research on instrumentation. Our research in physical optics has provided a differential microinterferometer to measure motions of microscopic organelles at the picometer level, and image-analysis techniques that allow observation and tracking of individual molecules on living cells with nanometer sensitivity. Our new nonlinear two-photon laser scanning microscope can image, with three-dimensional resolution, the distribution of sparse chemical markers within living cells. <P> <I>Fluctuations in Cooperative Systems. </I>The use of noise as a physical probe, which has been successful in nanometer-scale microelectronics and in composite networks, is being applied to studies of protein-folding dynamics, biological membrane channels, receptor aggregation, and percolation transport on the fractal and cooperative structures of cell membranes. <P> <I>Dynamics of Complex Fluids.</I> Phase transitions and fluctuations in lyotropic-lipid liquid crystals are studied as model systems for biological membranes. For example, diffraction of synchrotron x-radiation detects phase transformations and fluctuations. The hydrodynamics of boundary layers is studied with our optical method for direct measurements of fluid vorticity fluctuations. Fluid-fluid interface structures, interface fluctuations, diffusion in cytoplasm, and cooperative processes in percolation structures are also observed with sensitive optical processes.<BR> <H3>Current Research Projects</H3> <DL> <DT>Developmental Resource for Biophysical Imaging Optoelectronics (National Institutes of Health) <P><DT>National Instrumentation Facility for Optical Microscopy (National Science Foundation) <P><DT>Photophysics of Quantitative Microscopy for Living Cells (National Institutes of Health) </DL> Participants in these projects include postdoctoral associates A. Stout, W. Zipfel, S. Maiti, J. Mertz; visiting fellow J. Shear; visiting scientist E. Beaurepaire; technician K. Hodgson; administrative assistant M. Purvis; and graduate students I. Brust-Mascher, R. Williams, J. Guild, C. Xu, N. Switz, E. Brown, and J. Nichols.<P> <A HREF = "Webb_CV.html">Curriculum vitae and selected publications</A><BR><P> <HR WIDTH="70%"><BR> <CENTER><A HREF = "../cornell_pharmacology.html">Field of Pharmacology Home Page</A></CENTER> <BR> <HR> <BR> <TABLE BORDER=0 ALIGN=LEFT VALIGN=TOP CELLPADDING=5> <TR> <TD VALIGN=TOP><IMG Align=Top SRC="../faculty_pictures/webb_low.jpeg"></A></TD> <TD VALIGN=MIDDLE> <PRE>Watt W. Webb Applied and Engineering Physics 223 Clark Hall Cornell University Ithaca, New York 14853 USA <a href=mailto:www2@cornell.edu>e-mail</a>: www2@cornell.edu phone: 607-255-3331 FAX: 607-255-7658 </PRE> </TD> </TR> </TABLE>