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Theme and Variation: Students Research Supramolecular Chemistry

Jul 06, 2017


Group of students in the labInside a lab in the college's new science building—Macon F. Brock, Jr. Hall—four Randolph-Macon College students are conducting research this summer. Clad in lab coats and peering into microscopes, they are working under the guidance of Chemistry Professor John Thoburn as they each explore different aspects of supramolecular chemistry.

The Thoburn Group
The students—Melissa Mitchler '18, Noah Herrington '18, PJ Patel '19, and Emma Tiernan '19—are participating in R-MC's Schapiro Undergraduate Research Fellowship (SURF) program. SURF offers students the opportunity to conduct 10 weeks of full-time, original research during the summer, under the mentorship of a faculty mentor. Mitchler, Herrington, Patel and Tiernan—known affectionately as the Thoburn Group—are focusing their research on a family of miniature supramolecular cubes that are capable of encapsulating other molecules.

"The six sides of these boxes are made of molecules called porphyrins, which themselves can be found in biologically active compounds such as hemoglobin and chlorophyll," explains Thoburn. "The molecular boxes are held together by eight iron cations, one at each corner of the cube. It has been known for several years that these cubes could encapsulate 'guest' molecules. Many guests can be envisioned, including drugs and molecules that act as antennae to capture light."

The Research
Mitchler is working on developing a supramolecular cube that can open when light is shined on it. Cubes that open on light activation could be used as part of phototherapy—the release of drugs carried in the cubes when certain target tissues are irradiated.

Herrington is focusing on unusual guest molecules that can bind to the inner porphyrin walls, while Patel is working on replacing the iron atoms with ruthenium in the hope of making it easier to "open" the box to let the guest molecules in and out.

Tiernan is working on designing a molecular cube that can encapsulate quantum dots—clusters of cadmium and selenium atoms that absorb light and then emit light at a different frequency (fluorescence). The fluorescence can be absorbed by the porphyrin boxes and potentially used as an oxygen indicator.

Melissa Mitchler '18
This is Mitchler's second time participating in the SURF program.

"Last summer's research was such a rewarding experience because our lab group was like family," says Mitchler, a chemistry and biology major. "We supported each other and helped each other with our SURF projects. This summer I applied to SURF because I was very invested in my project—I had continued to work on it throughout the school year. Professor Thoburn is such a caring, patient and understanding research advisor, which makes working in his lab rewarding. Research is a great way to gain confidence and independence, and I've grown exponentially from the SURF experience."

Mitchler, who plans on pursuing a Ph.D. in chemistry, hopes that the SURF work she's doing will someday help lead to a discovery that will keep toxic drugs away from sensitive tissues as they reach their proper destination.

"Using these supramolecular cubes as a targeted delivery system would allow a new technique to fight cancerous tumors," says Mitchler, a member of Delta Zeta, Leadership Fellows, Service Fellows, and Beta Beta Beta. She is also a member of Phi Lambda Upsilon and serves as president of Order of Omega and Rho Lambda, president of Student Affiliates of the American Chemical Society, and as an intern for the Office of Student Life.

Mitchler will be joined on this project by LaStacia Sampson, a junior from Richmond Community High School. Sampson's summer internship in the Thoburn Group is being supported by the American Society's SEED program, which brings in high school chemistry students from disadvantaged backgrounds to college campuses to experience what it is like to be a research chemist and to experience how college works.

Noah Herrington '18
Herrington, a chemistry and Spanish major, is continuing a project that he began during last year's SURF program.

"Each day in the lab can vary quite a bit, because the way the research progresses is dependent on the success of previous steps," he explains. "When I arrive at the lab, I check up on any reactions I may have left to run overnight, run a 1H NMR to characterize a compound or check the progress of a reaction, and then proceed with a work-up. If I like the results of a reaction, I can think about whether I want to proceed with purification or the next step with a new reaction."

The SURF program, says Herrington, gives him practical experience that breaks the boundaries of the classroom.

"I enjoy experimenting and working with the practical aspects of what I've learned in a class," he says. "There's also the thrill that comes with hands-on research. It's exciting to work and feel like a scholar under the direction of a professor in a real research and laboratory setting."

Mentorship is key to the program's success.

"Professor Thoburn is the best advisor that anyone could ask for," says Herrington, whose post-R-MC plans include graduate school. "He adds his unique sense of humor to everyone's day and provides me with exceptional guidance, advice, and feedback on all my work, while also encouraging me to have more faith in my own abilities as a scientist."

PJ Patel '19
Patel, a chemistry major and biology minor, enjoys the challenges that research entails.

"Classes teach curriculum, but research is where students put critical thinking and lab practice together to expand upon their knowledge," he says. "It's exciting to think that what we discover today may be on the exam of a future student."

Each day of research reveals something new to Patel, who serves as president of R-MC's Pre-health Society and plans to attend medical school.

"A day can be filled with compound synthesis, purifications, various chemical characterizations, and literature review," he says. "We report to the lab at 8:30 a.m., strategize a plan for the day, and begin. Professor Thoburn is critical to the success of the project. In a field such as chemistry, there exists such a broad and rich existing body of knowledge that without an experienced scientist ready to guide us, we would be lost."

Drawing relationships between course content and research experience is exciting to Patel, the recipient of a summer stipend through the Jan M. Carter, MD '78 Medical Internship Program and a scholarship through the Dr. & Mrs. Marshall & Alice McCabe Pre-Med Endowed Scholarship.

"It shows us that what we learn in class is not just 'book knowledge'—it is used every day to solve real problems," he says.

Emma Tiernan '19
An engineering physics and chemistry major, Tiernan had long been interested in participating in the SURF program and applied after Thoburn encouraged her to do so. Tiernan's project entails synthesizing a larger supramolecular cube with palladium at the center of each "face" and then putting a quantum dot (a combination of two or more atoms that acts as a single atom) in the cube.

"The quantum dots are starting to be used when making television screens because they give off different colors of light," explains Tiernan, a member of Delta Zeta, the American Chemical Society, the Society of Physics Students, and Macon Women Engineers. "A few years ago, researchers at MIT and Harvard created an oxygen detector with a structure similar to that of one of my cubes' faces. When oxygen is present, light given off by the detector is quenched. Their indicator can be used to monitor the oxygen levels of cancerous tissues or tumors. My research goal is to create an even more sensitive oxygen detector that can be used within the medical realm."

The SURF experience is a great way for Tiernan to apply topics covered in many of her classes to her project.

"For example, I am combining my knowledge from my chemistry and engineering classes to help understand why the quantum dot acts as such a good fluorophore," she says. "I thoroughly enjoy working with Professor Thoburn. He is always there whenever I have questions and he gets very excited when reactions work out the way we want them to." Tiernan's
post-R-MC plans include graduate school, where she will pursue a master’s degree in aerospace engineering.

"My dream in life is to design commercial aircraft that emphasize passenger comfort rather than focus on fitting the maximum number of passengers in a small space," she says. "Hopefully in 15 years I'll be in Seattle designing aircraft for Boeing!"

Generous Support
The Schapiro Undergraduate Research Fellowship (SURF) program was introduced in 1995 as an endowment to support scholarly undergraduate research by R-MC students in all disciplines. The initial gift for the program was made by Benjamin Schapiro '64 and his wife Peggy.

The Schapiros' generosity provides students with the opportunity to conduct original research under the guidance of a faculty member. The SURF program demands that students experience a professional research environment. Students submit a research proposal for funding to faculty reviewers, emulating a competitive external review process. If funded, the student receives a modest summer stipend, and it is understood that the research should result in presentation of the findings at professional meetings and submission for publication where appropriate.

The college also provides free housing so students can engage in a number of activities as a community. Among these activities are seminar presentations by faculty members and visiting scholars. Results of the research are presented at the annual SURF Symposium and on Research Day in the spring in a celebration of the summer's activities.

The SURF program is co-directed by Art History Professor Evie Terrono and Serge Schreiner, the Dudley P. and Patricia C. Jackson Professor of Chemistry.