摘要:SummaryEngineering protein-based biomaterials is extremely challenging in bioelectronics, medicine, and materials science, as mechanical, electrical, and optical properties need to be merged to biocompatibility and resistance to biodegradation. An effective strategy is the engineering of physiological processesin situ, by addition of new properties to endogenous components. Here we show that a green fluorescent semiconducting thiophene dye, DTTO, promotes,in vivo, the biogenesis of fluorescent conductive protein microfibersviametabolic pathways. By challenging the simple freshwater polypHydra vulgariswith DTTO, we demonstrate the stable incorporation of the dye into supramolecular protein-dye co-assembled microfibers without signs of toxicity. An integrated multilevel analysis including morphological, optical, spectroscopical, and electrical characterization shows electrical conductivity of biofibers, opening the door to new opportunities for augmenting electronic functionalities within living tissue, which may be exploited for the regulation of cell and animal physiology, or in pathological contexts to enhance bioelectrical signaling.Graphical AbstractDisplay OmittedHighlights•The oligothiophene DTTO promotes the synthesis of microfibers inHydra vulgaris•DTTO co-assembles with proteins giving rise to fluorescent and conductive microfibers•The biofiber synthesis is an active process, based on protein synthesis•In situproduced hybrid microfibers have great potential in biolectronics and biomedicineSupramolecular Chemistry; Bioelectronics; Bioengineering