PROJECT SUMMARY In recent decades, bioimplants in human bodies have been more and more routinely used in almost every biomedical specialty, with the functions ranging from pathological and biological studies to medical treatments and restoration of body functions. Among all the different types of bioimplants, implantable electronic devices comprise a major category that provide highly accurate and programmed signal transductions. However, the longevity and stability of all types of bioimplants, including electronic devices, have been facing a common challenge, that is the excessive ingrowth of collagen and inflammation reactions around the device, which have been known as “foreign-body response (FBR)”—a type of immune-mediated reaction on foreign/synthetic material “invaders”. Even for the most successful, FDA-approved bioimplants that have been used for decades, excessive FBR can be provoked in many individuals, which is the primary cause of the device failure before their desired functional periods. For solving this commonly existing grand challenge, although a substantial amount of efforts has been made in the development of new biomaterial designs for suppressing FBR, the research has been almost exclusively focused on insulating-type polymers/hydrogels. To proceed to the next horizon of solving the immune-compatibility problem for implantable electronics using the most promising material family— electronic polymers, it is vitally important for us to develop a set of innovative material designs for electronic polymers for concurrently achieving superior immune compatibility and high electrical property. We propose to achieve this by intellectually addressing the extraordinary challenge of unprecedentedly interfacing immunology with semiconductor physics and polymer sciences, and experimentally combine the approaches of polymer synthesis, morphological engineering, device fabrication, electrical characterizations, in vitro cell tests, and in vivo animal tests. Specifically, the focuses of this research include four aspects: 1) developing new designs of semiconducting and conducting polymers for achieving immunocompatible chemical property; 2) developing “hydrogel-architecture” polymer semiconductors for realizing tissue-level elastic moduli for achieving immunocompatible physical property; 3) in vitro and in vivo study of the elicited FBR by these immunocompatible designs of electronic polymers; 4) combining the material and device developments to realize proof-of-concept immunocompatible devices, including electrophysiological devices, and transistor-based biochemical sensors. Based on the highly important uses of implantable electronics, we envision the realization of immunocompatible electronic devices from this research will create significant benefits and far-reaching impacts to a wide spectrum of biomedical areas.

PROJECT NARRATIVE Implantable electronics have prevalent applications in fundamental biological studies, disease diagnosis, and medical treatment, but have been facing a commonly existing challenge of causing inflammation reactions to the human body, which is known as foreign-body responses. To fundamentally solve this challenge, this project aims to create a new class of high-performance electronic polymers that have the suitable chemical and physical properties to evade the recognition by the human body’s immune system, therefore suppressing the foreign- body responses. This major breakthrough in the development of functional biomaterials will further allow us to realize two important types of implantable devices: electrophysiological recording and stimulating devices, and biochemical sensors.