Research from the University of Chicago's Pritzker School of Molecular Engineering has introduced new strategies to reduce scar tissue formation around implantable bioelectronics. These findings, detailed in a Nature Materials publication, may extend the functional lifespan of devices such as pacemakers and sensors by minimizing the immune system's foreign-body response.
The study, led by Assistant Professor Sihong Wang, suggests design modifications for semiconducting polymers used in implants. The immune system typically identifies these devices as foreign objects and encapsulates them with scar tissue over time, which can impair their function. "A lot of research groups are making very novel designs of implantable devices," noted Seounghun Kang, a postdoctoral researcher at Pritzker Molecular Engineering and co-first author of the paper. However, these groups face challenges related to long-term implantability.
The researchers adopted a dual strategy: integrating selenophene into the polymer backbone and adding immunomodulating materials to its side chains. "Based on these two strategies, we developed these new materials that not only exhibit good biocompatibility but also maintain the good electrical performance needed for a bioelectronic device," said Zhichang Liu, co-first author and PhD student in Molecular Engineering.
Tests conducted on mice showed up to a 68% reduction in collagen density around implants like pacemakers, potentially enhancing their efficiency over time. This research builds on previous work by Wang’s group on hydrogel semiconductors designed to improve body-machine interfaces. Both projects received funding through an NIH Director’s New Innovator Award granted to Wang in 2022.
Wang emphasized that addressing the foreign-body response is crucial for maintaining device stability and reducing patient side effects. He explained how scar tissue acts as an insulating layer that impedes signal transmission between organs and devices: “You need the biological signals to be able to efficiently go from the organ to the device,” he stated.
Moving forward, Liu indicated that efforts would focus on improving material stability while further decreasing immune reactions. "During this research, we also found some different strategies...such as reducing reactive oxygen species,” she mentioned.
Wang highlighted how interdisciplinary collaboration within UChicago Pritzker Molecular Engineering facilitated innovative breakthroughs: “When these two research spaces...start to interact at a deep level, what kind of new technological frontiers could be generated?” he asked rhetorically.
The study was supported by funding from several sources including the US National Institutes of Health Director’s New Innovator Award, National Science Foundation, and US Office of Naval Research.
Citation: “Immune-compatible designs of semiconducting polymers for bioelectronics with suppressed foreign-body response,” Li et al., Nature Materials, April 17, 2025.
###