Intrinsically Antifouling, soft and conformal bioelectronic from scalable fabrication of Thin-Film OECT arrays by zwitterionic polymers

Thin-film bioelectronic arrays, emerging as a new medical tool, offers significant opportunities for health monitoring, medical diagnosis, medical treatment, life science studies, etc. Thin film devices face several challenges, including biofouling which hinders targeted electrocoupling in complex biological environments, high surface Young's modulus that causes mechanical mismatches with biological matter, and poor surface adhesion that makes it difficult to conform to undeveloped biosurfaces. Here, we developed a universal lithography fabrication platform with high yield, uniformity, and precision to prepare a biomimetic thin-film organic electrochemical transistor (OECT) array featuring intrinsic biofouling resistance, tissue-like surface softness, and strong adhesion to undeveloped surfaces. This fabrication platform is based on the photolithography fabrication of zwitterionic-polymer-based conducting channels and hermetic encapsulation systems without compromising their electrical properties and low permeability. The all-zwitterionic feature softens the surface and helps prevent proteins and cells from approaching the encapsulation and channel surface, thus protecting the OECT array from interference from nonspecific protein and cell interactions. The strong capillary force from the hydrated zwitterions drives the thin-film device to conform well on nonplanar surfaces. Utilizing this biomimetic device, we successfully demonstrated cell-selective electrocoupling in the presence of white blood cells (WBCs) and simultaneously realized close and stable on-skin electrocardiogram (ECG) monitoring via good skin contact and robust epidermal surface lipid resistance. We envision that our process would provide a versatile platform for producing antifouling and flexible bioelectronic devices that seamlessly integrate with biological systems, and promote the practical application of thin-film bioelectronic arrays in real-life scenarios.