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Innovative Imaging

Dr. Tessa Calhoun of the University of Tennessee’s Department of Chemistry has focused her research on nonlinear microscopy. Recently, as a part of the Science Alliance’s Joint Directed Research Development program, Calhoun constructed a new microscope for use in nanoparticle interfacial chemistry. As a Collaborative Cohort fellow, Calhoun has focused her efforts on transient absorption microscopy. The results of her research have the potential to shed light on drug interactions with cell membranes.

According to Calhoun, the goal of her work as a cohort fellow is to image small molecule drugs as they interact with the membranes of living cells through advancing imaging technology. Observing a molecule’s interaction with a cell membrane has most commonly relied on fluorescence, exciting the molecule with a single pulse of light and waiting for it to spontaneously emit. Unfortunately, not all systems fluoresce.

To bypass this difficulty, Calhoun uses transient absorption, a method that adds a variable second pulse of light, to stimulate a response. This particular technique has been used before, but rarely with biological systems.

“I built my first version of this experiment as a post-doc and brought it here,” said Calhoun. “The Cohort really allowed me to build the second generation. “ Calhoun’s team is attempting to advance this technique by speeding up how quickly images are produced, as well as broadening the range of energies used to create the imaging.

In addition to expanding her research, Calhoun says the Collaborative Cohort fellows formed a helpful community of cross-disciplinary scientists who were able to share information with each other on a variety of topics.

“Getting together with a group of diverse scientists, we’re all tenure track so in a broad sense we all have the same goals so there’s a lot of common ground there, as you go through those struggles together,” said Calhoun. She added that the regular meetings between the cohort fellows have opened the door to possible future collaborations.

“I think a huge goal of it was starting to facilitate cross talk between such different disciplines and people so passionate about what they’re doing, and at the stage in their career where they’re still trying to explore and expand,” said Calhoun.

Calhoun plans to continue her work in transient absorption microscopy after the completion of her term with the Collaborative Cohort.