Ph.D. Student Karina Torres-Castro Applies Fellowship to Advance Pancreatic Islet Transplant Therapy

A June 2020 World Health Organization survey confirmed that medical professionals’ urgent work to combat COVID-19 has severely disrupted prevention and treatment of noncommunicable diseases such as diabetes. The World Health Organization has reissued calls for concerted effort and innovation in the treatment of these diseases.

A research team led by Nathan Swami, professor of electrical and computer engineering at the University of Virginia, was already focused on the need for innovation, working to improve a treatment for Type 1 diabetes that frees patients from insulin shots. In Type 1 diabetes, the immune system mistakenly attacks insulin-producing pancreatic cells, requiring patients to manage their blood sugar levels through a daily regimen of insulin therapy. According to the American Diabetes Association, nearly 1.6 million Americans have Type 1 diabetes, including about 187,000 children and adolescents.

Swami’s team develops microsystems for transplant therapies based on pancreatic islets. The islets produce insulin and glucagon, two hormones that regulate blood sugar. Islet transplantation has allowed some patients to live without the need for insulin injections, but there are no guarantees.

“It’s hard to know which islets will work when introduced into the patient’s bloodstream,” Swami said. Not all islets are able to integrate with the vascular system and withstand immune responses. Early detection of islet rejection or dysfunction remains a challenge.

Karina Torres-Castro, a Ph.D. student of electrical engineering and one of Swami’s advisees, has built a micro-device to select the most transplant-worthy islets recovered from donors. These are the islets that allow blood vessels or capillaries to infiltrate them, which in turn allows the islets to access the blood supply and secrete insulin based on glucose levels.

Torres-Castro has earned a Sture G. Olsson fellowship to support her research and academic study. An endowment from Sture Gordon Olsson, a 1942 UVA mechanical engineering graduate, provides fellowships to graduate students in the UVA School of Engineering whose research focuses on systems approaches to biomedical engineering.

“My research shows that secretions from stem cells strengthen the islet’s basement membrane, which makes the islet more amenable to infiltration by blood vessels,” Torres-Castro said. “The resulting biomechanical alterations to single islets can be used as a marker to assess each islet’s quality in a non-destructive way and efficiently recover insulin-producing islets from donors.”  

Torres-Castro joined Swami and other group members to present the team’s research at MicroTAS 2020, an October 2020 gathering of experts in miniaturized systems for chemistry and life sciences sponsored by the Chemical and Biological Microsystems Society.

Torres-Castro is interested in tiny systems or chips that use mechanical or electrical forces to manipulate biological entities such as cells, tissue and bacteria. She combines fluid mechanics at the micro- or nano-scale with electric fields and other types of forces to design and fabricate chips, using standard microelectronics fabrication techniques and 3-D printing for biomedical applications. This field of study has its own name, BioMEMS.

Torres-Castro became interested in the field while earning her master’s degree in microelectromechanical systems, or MEMS, at the Instituto Tecnológico de Costa Rica. Her work on sensitized solar cells required experimentation with different materials and assembly methods. Whereas the materials and methods are different, the design and fabrication of microdevices are similar processes.

“The end goal is to develop a platform that allows you do certain measurements and work to improve it, so it becomes more and more efficient. What I like about these topics is that both seek to improve people’s quality of life,” Torres-Castro said.

UVA’s diversity and inclusion vision, strong focus on research, and co-located schools of engineering and medicine appealed to Castro-Torres, as did the multidisciplinary research underway in Swami’s group.

“We have electrical, chemical, material and biomedical engineers working together in the same lab with chemists, physicists and microbiologists,” Torres-Castro said. “This enriches our discussions and allows us to tackle problems from different perspectives. I think this has been strategic for forging collaborations not only inside the engineering department but also with other departments and the School of Medicine.”