A frequency-dependent phase-transition bioelectronic device with in-situ signal-filtering and Janus-adhesive capabilities for low-artifact sensing and tendon repair.

Mechanical and electrical mismatches exist at bioelectronic interfaces and tissue interfaces under complex environments, which easily lead to signal artifacts and adhesive residues. As a result, it is difficult to achieve both high sensitivity and anti-interference performance in bioelectronic interfaces. Inspired by multiple biological systems, this work proposes a multi-scale biomimetic construction strategy (JAH). An ionic-electronic hybrid conductive hydrogel with frequency-dependent phase transition is designed, and a Janus structure is constructed. In this way, two core functions, in-situ signal filtering and janus adhesion, are realized simultaneously. The designed JAH device is founded on a hybrid ionic-electronic conductive network as its chemical and electronic basis, ensuring high sensing sensitivity. By leveraging the energy dissipation characteristics of the frequency-dependent phase-transition hydrogel, the target signal is effectively decoupled from dynamic interference signals at the same frequency, achieving a 3.5-fold enhancement in signal-to-noise ratio. A gravity-guided and functional-group-induced synergistic process was employed to monolithically fabricate the Janus structure, achieving up to a 27-fold difference in adhesion energy while maintaining high sensitivity (gauge factor GF∼5.73, superior to reported Janus hydrogels). In addition, the material system balances the contradiction between weak bonds for in-situ signal filtering and strong bonds for maintaining material toughness (elongation at break ∼2523%, strength ∼117.7 kPa). In summary, JAH achieves low interfacial impedance, high mechanical toughness, strong anti-interference ability and high sensing sensitivity at the same time through the combination of hybrid conduction, frequency-dependent phase transition and biomimetic janus structure. Experiments show that JAH can be used for motion sensing, low-artifact electromyographic signal acquisition, and suture-free repair of ruptured tendons. This work provides an important foundation for high-precision bioelectrical signal collection, high-quality tissue repair, early diagnosis and active rehabilitation.