High-density soft bioelectronic fibres for multimodal sensing and stimulation.

There is an increasing demand for multimodal sensing and stimulation bioelectronic fibres for both research and clinical applications. However, existing fibres suffer from high rigidity, low component layout precision, limited functionality and low density of active components. These limitations arise from the challenge of integrating many components into one-dimensional fibre devices, especially owing to the incompatibility of conventional microfabrication methods (for example, photolithography) with curved, thin and long fibre structures. As a result, limited applications have been demonstrated so far. Here we use 'spiral transformation' to convert two-dimensional thin films containing microfabricated devices into one-dimensional soft fibres. This approach allows for the fabrication of high-density multimodal soft bioelectronic fibres, termed Spiral-NeuroString (S-NeuroString), while enabling precise control on the longitudinal, angular and radial positioning and distribution of the functional components. Taking advantage of the biocompatibility of our soft fibres with the dynamic and soft gastrointestinal system, we proceed to show the feasibility of our S-NeuroString for post-operative multimodal continuous motility mapping and tissue stimulation in awake pigs. We further demonstrate multi-channel single-unit electrical recording in mouse brain for up to 4 months, and a fabrication capability to produce 1,280 channels within a 230-μm-diameter soft fibre. Our soft bioelectronic fibres offer a powerful platform for minimally invasive implantable electronics, where diverse sensing and stimulation functionalities can be effectively integrated.