A biocompatible elastomeric organic transistor for implantable electronics

Abstract Implantable bioelectronics transforms the interface between electronics and biological systems, enabling continuous in situ monitoring and modulation of electrophysiological signals. A critical challenge remains in the mechanical mismatch between conventional rigid electronic components and soft biological tissues, which can lead to tissue damage and inflammation. Additionally, the low biocompatibility of existing soft electronic components exacerbates these issues. Here, we present biocompatible, elastomeric organic field-effect transistors (OFETs) designed for implantable applications. These OFETs utilize a blend of semiconducting nanofibers and medical-grade elastomers, such as poly[(dithiophene)-alt-(2,5-bis(2-octyldodecyl)-3,6-bis(thienyl)-diketopyrrolopyrrole)] (DPPT-TT) and bromo butyl rubber (BIIR), respectively. This composite film exhibits exceptional mechanical stretchability and biocompatibility with similar Young’s modulus with human tissues, maintaining high electrical performance even under 50% strain. In addition, the integration of biocompatible dual-layer Ag-Au metallization results in robust, stretchable, and corrosion-resistant electrodes. In vitro assessments with human dermal fibroblasts and macrophages confirmed the biocompatibility of the materials, showing no adverse effects on cell viability, proliferation, or migration. In vivo implantation studies in BALB/C mice revealed no significant inflammatory response or tissue damage, underscoring the potential for long-term biointegration. Our biocompatible and stretchable OFETs demonstrated stable operation in logic circuits, including inverters, NOR, and NAND gates under physiological conditions, offering a promising platform for various medical applications, from diagnostics to therapeutic interventions.