Dunn participates in Biophysics REU program at Clemson University

Dunn participates in Biophysics REU program at Clemson University

May 5, 2020

Since he began his college career in 2016, Maryville College senior biochemistry major Logan Dunn ’20 has had an interest in pursuing a career in biomedical research.

Last summer, he had an opportunity to complete an internship that further clarified that path.

In the Biophysics Summer REU (Research Experiences for Undergraduates) program at Clemson University, Dunn worked in labs at the Clemson Light Imaging Facility (CLIF) and the Clemson Nanomaterials Institute (CNI), where he participated in interdisciplinary research.

Dunn, who transferred to Maryville College from Pellissippi State Community College in fall 2018, learned about the internship during his first semester at MC. He took a research seminar class, which is intended to help students build a foundation for their Senior Study.

One of the distinctive features of a Maryville education, the Senior Study requirement calls for students to complete a two-semester research and writing project that is guided by a faculty supervisor. According to the College’s catalog, the Senior Study program “facilitates the scholarship of discovery within the major field and integrates those methods with the educational goals fostered through the Maryville Curriculum.”

Not having completed his science-related major required courses yet (he had completed all of his general education requirements and most electives before transferring), he was unsure about his Senior Study topic. His professor recommended that he look into National Science Foundation (NSF) REU programs, which take place during the summer and could likely provide valuable research that he could use as part of his Senior Study.

Clemson’s REU program caught his attention, because it “emphasized a partnership between interns working in two labs and a focus on interdisciplinary work.”

“They listed project descriptions along with the primary investigator (PI) and the methods each project would use. I thought the projects all sounded amazing,” said Dunn, who is from Maryville, Tenn. “Some of the project methods they had listed were the basis of Nobel Prizes awarded within the last decade, most projects incorporated some form of microscopy I had never used—or heard of—and all of them would’ve fostered my personal growth as a scientist.”

Interdisciplinary Research in Two Labs

When he arrived at Clemson University, Dunn and other interns underwent a “biophysics bootcamp” during the first week to practice or learn laboratory techniques related to the participants’ respective projects. This included transforming E. coli with plasmid DNA to make the bacteria express a fluorescent protein, using electrophoresis to determine the size of the protein and isolating and purifying the fluorescent protein, he said. These were not new techniques for Dunn; having transformed bacteria in Dr. Jennifer Brigati’s genetics lab at Maryville College prior to the REU, he felt “extremely confident” in completing the procedure and explaining the underlying science.

For the remainder of his 10-week internship, he split his time between two labs. At the Clemson Light Imaging Facility (CLIF), his group focused on furthering the capabilities of a technique called multiphoton imaging (MPI).

“This method uses multiple photons in the far-red and/or near infrared regions of the electromagnetic spectrum; photons with these wavelengths are non-damaging to cells and can more readily penetrate tissues without being absorbed,” Dunn explained. “Currently, this imaging method is limited to roughly one centimeter deep in live organisms, and the goal of our work was to design and optimize a more efficient imaging probe using carbon-based nanomaterials that would ultimately be capable of imaging at increased depths.”

Work at the Clemson Nanomaterials Institute (CNI) focused on the preparation and physical characterization of the single-walled carbon nanotubes (SWCNTs) they used as nanomaterial probes.

“SWCNTs were given induced defects by a planetary ball mill, which is essentially an instrument that grinds the nanomaterial like a mortar and pestle,” Dunn said. “In total, there were five average defect densities. Some of the physical analyses I performed included scanning electron microscopy, transmission electron microscopy and Raman confocal microscopy. Final preparation of the SWCNTs occurred at Clemson’s Light Imaging Facility, where three stock samples were made for each defect density. Two of these stock samples were coated with protein, one with bovine serum albumin (BSA) and one with fibrinogen.”

Outside of the lab, he stayed busy, participating in a variety of activities related to his internship. His REU group had the opportunity to visit biotechnology companies and organizations, such as Greenwood Genetic Center and RayBiotech.

He participated in one to three professional development workshops every week – one just for program participants and the others for REU students across campus. By the time he completed his internship, he had attended 21 workshops, with topics ranging from data analysis tools to funding graduate school.

Dunn also had several opportunities to present his work. A journal club held every other week allowed interns to present and discuss recent research done by others, and biophysics seminars provided opportunities to hear from professors who presented their research. The students, including Dunn, were required to give two oral presentations about their respective project, and they made posters about their work and presented them at a campus-wide research symposium. 

Senior Study Research

Work completed during his REU internship is the basis of Dunn’s Senior Study, and he spent much of this academic year reviewing literature, revising his writing and improving the presentation and interpretation of his results, he said.

His study, titled “Evaluating the Cellular Uptake and Biocompatibility of Single-Walled Carbon Nanotube Imaging Probes,” is based on the project at the Clemson Nanomaterials Institute, which focused on furthering the capabilities of MPI.

“Current imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI) can distinguish millimeter-sized objects, but MPI is capable of distinguishing micrometer-sized objects, which is the scale of most cells in the human body,” Dunn explained. “With enough improvement, this imaging method could be adapted for use in the medical field to collect images several centimeters into tissue. It would be particularly useful for detecting some forms of cancer in their infancy, which would likely improve patient outcomes.”

His project focused specifically on “evaluating the uptake of SWNCT imaging probes by macrophage cells and evaluating the cellular response to each,” he said. 

“The nanomaterial probes had five average defect densities and three surface coatings:  bare, BSA-coated, and fibrinogen-coated,” he said. “After exposing macrophage cells to a given concentration of each of these 15 samples, we used hyperspectral imaging to qualitatively confirm uptake by the cells. Then, we performed flow cytometry to characterize differences in size and cell granularity after uptake. To evaluate the cellular response to the nanomaterials, I used two microplate assays, one for generation of reactive oxygen species and one which measures mitochondrial activity within cells to determine viability. Both assays were performed at five doses of increasing concentrations.

“The biggest takeaways from my part in this project were that the BSA-coated SWCNTs were preferentially taken up by cells in comparison to bare- and fibrinogen-coated nanomaterials, and that the BSA protein also seems to mediate any negative cellular response to some extent in comparison to the other nanomaterial surfaces.”

‘Impressive’ Work

Dunn’s Senior Study was so impressive that it was recommended by the Maryville College Division of Natural Sciences as an exemplary thesis for the library’s permanent collection.

His work also could be published in an academic journal. A manuscript about the project at the Clemson Nanomaterials Institute is in progress, and Dunn will be a co-author when it is submitted.

“It will make me feel very proud if/when it’s eventually published,” Dunn said. “I was given an amazing opportunity, and I did my best to take advantage of it every moment I was there. The work itself reaffirmed my desire to pursue work in science, and I’m excited to get the chance to participate in that level of work again in graduate school.”

Dr. Jerilyn Swann, associate academic dean, director of institutional research and professor of biology at MC, said Dunn’s participation in this level of research as an undergraduate “is impressive enough by itself.”

“That they valued his contribution to the work highly enough to make him a co-author is extraordinary and indicates just how special he is,” Swann said. “He will surely have his choice of excellent opportunities for graduate school and beyond.”

Dunn also impressed his supervisor at Clemson. Wren Gregory, a research assistant and Ph.D. candidate in physics and astronomy at Clemson University and the laboratory manager of the Clemson Nanomaterials Institute, said it was “an absolute pleasure” to work with Dunn on the project.

“His knowledge of biology and ability to quickly learn complex aspects of materials science was very impressive,” Gregory said. “He was a notably hard worker, even outshining graduate students I’ve worked with. I am excited to see where he will go with his future and would hire him to work in our laboratory without a second thought.”

Future Plans

After graduating from Maryville College, Dunn plans to pursue a doctoral degree that would lead to a career in biomedical research. He recently accepted an offer of admission to the biochemistry Ph.D. program at the University of Tennessee, Knoxville, which he will begin in the fall. He said his research experience, both through his internship at Clemson and through his Senior Study at Maryville College, helped distinguish him from his peers during the application process.

“This research really clarified the number of paths I could go with research to improve medical care one day,” Dunn said. “The people I worked with stressed being able to explain the fundamental physics underlying my results, and I think keeping that mindset in the lab will continue to benefit me down the road. I was given the chance to use lab instruments and perform experiments many of my peers have never heard of, and I think that shows professors and possible PIs my versatility in the lab as a student.”  

Written by Chloe Kennedy, Assistant Director of Communications

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