Kelley Sullivan

Associate Professor, Physics and Astronomy



A new fluorescence microscopy lab will be built in the physics department starting in the Fall of 2011.  Research in the microscopy lab will be focused around a novel imaging technique known as fluorescence photoactivation localization microscopy, or FPALM.  Prior to the advent of FPALM and similar “super-resolution” imaging techniques, our ability to clearly image small features was limited to tens of microns by the optical diffraction limit of currently available lenses.  FPALM circumvents this optical limit by taking advantage of photoactivatable dyes to selectively light up random portions of a fluorescent sample, then building a composite image from many image frames taken with different parts of the sample lit.  In this way, FPALM can resolve features on the order of tens of nanometers – a 1000-fold improvement!  The images at right show the remarkable improvement in image resolution provided by FPALM.

FPALM can be used to study both physical and biological systems, and projects can be developed to offer opportunities for students to gain research experience in fluorescence photo-physics, optics, biophysics, medical imaging, and computer programming.  A few current project ideas include:

1. Characterization of new photoactivatable probes

2. Simulated and experimental investigations of imaging errors due to perturbations in the FPALM physical alignment and imaging procedure

3. Comparison of diffusion measurements made via FPALM and MP-FRAP (an alternative fluorescence microscopy technique)

4. Imaging physical samples, such as nano-fabricated structures

Students are also encouraged to participate in the first year construction phase, which will require skills in mechanical assembly, optical alignment and computer programming in Labview and Matlab. 


Images of a small cell tagged with the photo-activatable probe Kaede.  In (A), the image is produced using a diffraction-limited technique.  In (B), the image is produced using PALM (a similar technique to FPALM).  Panels (C) and (D) are magnifications of panel (B).  Image credit: E. Betzig et. al.  Science. 313, 1642 - 1645 (2006).