As one of 10 students selected for Westminster College’s 10th annual Summer Research Fellowship, Trinity Lin, a sophomore biology major from Taipei, Taiwan, spent her summer investigating if green tea extracts can inhibit the growth of some oral bacteria that cause cavities. Lin conducted her research, “Inhibiting Streptococcus Mutans Biofilm Using Peptide Fragments and Green Tea Extract,” under the guidance of Dr. Joshua Corrette-Bennett, associate professor of biology and molecular biology.  

As a pre-dental student, Lin was drawn to oral health research, particularly ways to prevent cavities caused by Streptococcus mutans (S. mutans), a common oral bacterium. She was interested in green tea extract because it is widely available and has shown promise in inhibiting the bacterium’s cavity-causing properties. 

“I was intrigued by green tea extracts because it’s a very common household item, yet research showed it effectively inhibited the cariogenic properties of S. mutans,” said Lin. 

Lin’s project explores methods of inhibiting S. mutans biofilm formation using SspB peptides and green tea extracts. In her experiments, she grew S. mutans with either SspB peptides or green tea extract, stained the resulting biofilm and used a spectrophotometer to measure the amount of stain. She also spread bacteria from the cultures onto agar plates and grew them to determine the number of bacteria present. 

“The result was that high concentrations of green tea extracts kill the bacteria and thus inhibit biofilm formation. Low and medium concentrations of green tea extracts enhance bacterial growth but inhibit biofilm formation, which was counterintuitive and surprising,” said Lin. “High concentrations of SspB peptides inhibit both bacterial growth and biofilm formation. Medium and low concentrations of SspB peptides enhance bacterial growth and biofilm formation, which contradicts with the reference paper and is unexpected,” said Lin. 

Students participating in the Summer Research Fellowship are supported by the Drinko Center for Undergraduate Research and work with a faculty member who serves as a guide and mentor. 

Lin said Corrette-Bennett emphasized the importance of focusing on the research process rather than becoming discouraged by unexpected results. His guidance also extended beyond the lab, where he encouraged her to maintain a healthy work-life balance. 

“He also values work-life balance. He reminded me to go out into the sun and not stay in the lab overtime,” said Lin. “I not only learned a lot of technical skills from him, but also the right mindset that will guide me through the path in biological research.” 

Corrette-Bennett said Lin quickly mastered new techniques and laboratory equipment, allowing her to obtain interesting results in a relatively short period of time. He looks forward to continuing to work with her as she builds on the project for her capstone research. 

“Summer research experiences often serve as a launching pad for students who want to dive deeper into various topics during their junior and senior years at Westminster or at other research institutions,” he said. 

For Lin, the most challenging part of the project was preparing the green tea extracts. Pigments in the extracts interfered with the staining process, making it difficult to obtain accurate results. After several weeks of trial and error, she found that filtering the extracts twice using filters with smaller pore sizes resolved the issue. 

Lin serves as the vice president for the pre-dental society on campus. She is part of the 3+4 dental matriculation program and plans to attend Case Western Reserve University School of Dentistry upon graduation. 

Sponsored by the Drinko Center for Undergraduate Research, Summer Research Fellowships at Westminster College allow students to conduct hands-on research and creative projects under the guidance of our experienced faculty mentors. 

Learn more about Westminster’s Pre-Dental Program. 

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By  Kristen Aleprete  
Kristen Aleprete is a staff writer in Westminster College’s Office of Marketing and Communication.  
  

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