With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Biteen at the University of Michigan is developing a microscope to measure position and motion of biomolecules in living cells with a super high resolution (at the nanometer scale). This super-resolution microscope combines emerging high-resolution microscopy techniques and the unique properties metal nanoparticles where metal nanoparticles strongly affect the fluorescence emission from nearby dye molecules. Professor Biteen works on using the high-sensitivity microscopy to understand the interaction between metal nanoparticles and the dye molecules and to control coupled emission. She is working toward a real-time, non-perturbative, biocompatible microscope for live-cell imaging. Professor Biteen works closely with undergraduate women students and students from other under-represented minority groups. She is promoting science as an exciting field to a broad audience by supporting public lectures and developing hands-on demos for middle school girls.
Single-molecule, super-resolution microscopy enables direct investigations of physical and optical effects far below the half-micron diffraction limit of light, but this technique is restricted in practical applications by the limited brightness of probes relative to the background, especially in cellular samples. Plasmonic nanoparticles (NPs) readily produce over hundred-fold field intensity enhancements to brighten proximal dyes, but the modified dye emission also yields localization biases that have not yet been fully characterized due to the limitations of conventional experimental approaches. Professor Biteen is improving the resolution of single-molecule imaging with NP plasmonics. State-of-the-art single-molecule fluorescence experiments on dyes coupled to metal NPs can directly measure the effects of plasmonic NPs on proximal dyes. Therefore, the single-molecule readout can inform models of dye-NP interactions, while at the same time, plasmonic enhancement can improve the single-molecule fluorescence brightness. Professor Biteen is working toward high-accuracy, nanometer-scale, plasmon-enhanced super-resolution microscopy by: (1) measuring the changes in dye molecule intensity, spectrum, direction, and polarization of emission produced by a plasmonic NP, (2) controlling the dye-NP coupling by tuning the excitation polarization and frequency according to the relationships determined in objective 1, and (3) super-resolving the positions and movements of membrane proteins in living cells prepared on plasmonic surfaces.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
