Credits: Photo: Tom Gearty/MIT.nano Previous image Next image Beta defensins are a class of antimicrobial peptides that vary in size from 61 to 183 amino acids. More than 3,000 beta defensins had been identified prior to this year — until undergraduates in a lab class taught by associate professor of chemistry Bradley Pentelute synthesized some that had never been synthesized or characterized before. Part of the interest in these peptides stems from their potential ability to elicit an immune response to pathogens. Pentelute is collaborating in this project with researchers at Massachusetts General Hospital, and the beta defensins synthesized by the students will be tested in the hopes that some may lead to new varieties of antibiotics — a high priority in an era when antibiotic resistance is becoming an urgent concern.