Department of Applied Physics

Description

Biophysics

We optically probe single copies of fluorescent molecules in solution and in living cells, one at a time, with a combination of single-fluorophore labeling, active-control superresolution microscopy, stimulated emission depletion microscopy, FRET/polarization studies, and fluctuation analysis. In collaboration with appropriate biologists in the BioX program and others, we seek to understand the dynamical behavior of single biomolecules such as signaling proteins or photosynthetic antennas when ensemble averaging is removed, and we are measuring the protein localization patterns both in bacteria and in eukaryotic cells beyond the diffraction limit in three dimensions. A new kind of trap we have invented, the ABEL trap, allows us to grab and manipulate single fluorescent objects in solution for extended analysis. Not only can changes in fluorescence properties be sensed, but also changes in diffusion and electrokinetic mobility.

Nanoscience and Quantum Engineering

We optically probe single copies of fluorescent molecules in solution and in living cells, one at a time, with a combination of single-fluorophore labeling, active-control superresolution microscopy, stimulated emission depletion microscopy, FRET/polarization studies, and fluctuation analysis. In collaboration with appropriate biologists in the BioX program and others, we seek to understand the dynamical behavior of single biomolecules such as signaling proteins or photosynthetic antennas when ensemble averaging is removed, and we are measuring the protein localization patterns both in bacteria and in eukaryotic cells beyond the diffraction limit and in three dimensions. A new kind of trap we have invented, the ABEL trap, allows us to grab and manipulate single biomolecules in solution for extended analysis. Not only can changes in fluorescence properties be sensed, but also changes in diffusion and electrokinetic mobility.

Courses Taught

• Single-Molecule Spectroscopy and Imaging
• Physical Chemistry

Selected Publications

• Single-molecule motions enable direct visualization of biomolecular interactions in solution
• Microscopy beyond the diffraction limit using actively controlled single molecules
• Extending Single-Molecule Microscopy Using Optical Fourier Processing
• Super-Resolution Fluorescence Imaging with Single Molecules
• Exploring bacterial cell biology with single-molecule tracking and super-resolution imaging
• Single-molecule spectroscopy of photosynthetic proteins in solution: exploration of structure–function relationships
• New Directions in Single-Molecule Imaging and Analysis