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Ira Herman in his lab with Anita Geevarghese, A12
Photo: Kelvin Ma

Eureka: Scientists and Engineers in Their Own Words

Healing Chronic Wounds

“Normally, when you injure or cut yourself, tiny blood vessels regrow in the wound through a process called angiogenesis. That’s the budding and branching of new areas of circulation from existing ones. In the case of chronic wounds like diabetic ulcers, though, the angiogenesis that normally happens is disabled. So the wound stays open.

How do you treat this? Well, in the 1990s, my lab discovered that an enzyme called collagenase, which is made by the bacterium Clostridium histolyticum, did an incredibly good job of promoting healing. We started investigating it, and it turned out that the product of the enzyme, a chunk of protein called a peptide, was really doing the work.

In the last few years, we’ve been able to synthesize and enhance similar peptides in the lab, and are trying to tailor them to specific types of wounds. Right now, we’re using them to treat diabetic ulcers in lab animals, and the results look very promising.

At the moment, there’s only one FDA-approved drug out there to treat chronic wounds in diabetic patients. We think these new peptides can do a much better job than what’s already out there, and we’re hoping to get to clinical trials sometime this year.”

—Ira Herman, director of cellular and molecular physiology programs at the Sackler School of Graduate Biomedical Sciences and Tufts University School of Medicine

Understanding PTSD

“People who develop post-traumatic stress disorder have been exposed to very severe traumatic events, such as combat, rape, childhood abuse, and major car accidents. But here’s the interesting part: not everyone who experiences trauma develops PTSD. Why not? That’s the million-dollar question.

To help answer it, we’re doing an ongoing study with identical twins. They all have the same DNA and the same upbringing. The only major difference between them is that one went to Vietnam, was exposed to trauma, and developed PTSD.

We’re taking brain scans of these twins, and have found a couple of interesting things. There’s an area of the brain called the dorsal anterior cingulate cortex that processes conflict. In people with PTSD, it’s hyperactive. But it’s also hyperactive in their identical twin—the one who doesn’t have the disorder. It might mean that people with this type of brain activity are especially susceptible to PTSD if exposed to trauma.

If this finding is proven to be reliable, brain scans might one day be used as a screening technique. Say you have people who are about to go into traumatic situations, like firefighters, police officers, or combat soldiers. You might be able to determine with a brain scan who would be more likely to develop PTSD, and maybe limit their exposure to trauma.”

—Lisa Shin, professor of psychology, School of Arts and Sciences

Coded Messages Via Bacteria

“We were sitting around one day, and said, ’Well, we can send messages with chemistry—maybe we can think of a way to send them with biology.’ And we came up with the idea of using genetically modified E. coli bacteria. Using fluorescent proteins, we engineered seven different strains of bacteria that glow in different colors, and then designed a code using those colors.

To send a message, you put tiny dots of the bacteria onto a piece of nitrocellulose, which looks basically like paper. Once you do that, the cells are invisible. To develop the message later, you just press that piece of nitrocellulose onto a nutrient-rich gel, and transfer the bacteria so they can grow again. One cell will lead to a colony, and that colony after a few hours will glow. You don’t even need a microscope to see it.

Using bacteria to send a coded message also gives it a few different levels of security. First, nobody knows there’s a message in front of them because the bacteria are microscopic. Second, you can create a code that’s hard to break—you could have four or even five colors that correspond to a single letter. And third, you need to use just the right nutrients to develop the message.”

—David Walt, Robinson Professor of Chemistry, School of Arts and Sciences

DAVID LEVIN is a freelance science journalist in Boston. A former web producer for NOVA (PBS), he has been awarded science journalism fellowships by the Woods Hole Oceanographic Institution, the National Center for Atmospheric Research, and Carnegie Mellon University.

 
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