With NSF Funding, Biomedical Engineer Paving the Way for Better Injury Repair

Kara Spiller, PhD, an assistant professor in the School of Biomedical Engineering, Science and Health Systems, has received a prestigious NSF CAREER award.
Kara Spiller, PhD, an assistant professor in the School of Biomedical Engineering, Science and Health Systems, has received a prestigious NSF CAREER award.

Kara Spiller, PhD, an assistant professor in the School of Biomedical Engineering, Science and Health Systems at Drexel University, has received a National Science Foundation’s (NSF) Early Career (CAREER) award to develop a new technology that will better control the modification of biomaterials.

The NSF’s CAREER program offers the foundation’s most prestigious awards in support of early-career, non-tenured faculty who have the potential to serve as academic role models in research and education.

Spiller is studying ways to manipulate the body's immune system, heal injuries and fight against disease. One type of immune system cell, called macrophages, are the body’s first natural defense against infections and other types of damage. The success of implanted biomaterials — say, a scaffold to seal a hole in an organ after a tumor is removed – hinges on the behavior of these immune system cells.

Macrophages are versatile cells, constantly shifting their roles in response to cues from their environment. For example, “pro-inflammatory” macrophages clear bacterial infections and tumors and “pro-healing” macrophages promote chronic wound healing. “Pro-angiogenic” macrophages promote the vascularization of implanted biomaterials. Therefore, there is a big need in the biomedical research community for a strategy to precisely control the actions of infiltrating macrophages, particularly in the context of complex biomaterials, such as a bioprosthetic heart valve.

“We want to create the perfect environment for the biomaterial to work with your immune system cells and integrate with surrounding tissue. So, we need very precise control over the bioactive cues to your cells,” Spiller said. “Right now, there is no universal way to do that.”

The NSF has awarded Spiller funding to solve this problem by determining how changing affinity binding interactions and the biomaterial microenvironment will control the release of cytokines – small proteins that talk to each other to control macrophages in sites of inflammation. Spiller plans to determine how biotin-avidin binding kinetics and biomaterial properties affect the speed and pathway of these proteins being released into the body and subsequently activating macrophages.

Spiller says these experiments could have a diverse range of potential applications.

“If you needed a fast-release and slow-release formulation in the same pill, for example, you could use this technology to release your drug at the different rates,” Spiller said. “Or, with tissue engineering, let’s say you wanted to grow and organ in a dish, you might need certain factors to be locally presented to your cells in the biomaterials at certain times.”

The results of the project will pave the way for the design of biomaterials that can modulate the immune system for biomedical applications, while contributing a fundamental understanding of binding interactions in three dimensions.

Spiller’s CAREER project also includes an educational component. As the daughter of a Philadelphia School District teacher, Spiller knows there are few opportunities for students to study engineering in their elementary math and science curriculums. Spiller plans to design a curriculum for teaching students engineering principles from kindergarten until third grade. Spiller and her undergraduate biomedical engineering students will visit classrooms three times per year to lead activities, like showing how packing peanuts dissolve in water and then can be molded into new structures, and using gelatin and food coloring to model diffusion.

The primary goal of the program will be to pilot educational activities that can be shared with other teachers. According to the 2014 National Science Board’s Science and Engineering Indicators report, only 39 percent of elementary school teachers feel “very well” prepared to teach STEM principles to children, and only 30 percent feel well prepared to encourage female students to take an interest in science.

Secondary goals of the program are to improve mentorship skills of Drexel students and also to collect preliminary data on how well the program will improve students’ STEM performance.

“There is almost nothing in the literature in terms of engineering resources for childhood education, and also there are not a lot of diverse role models for engineering students this young,” Spiller said. “My hypothesis is that if you keep repeatedly introducing students to engineering principles throughout their early childhood years, then, as they get older, then they will be more interested in science and math than the kids who just got a one-time engineering activity.”