• Biocompatible ECochG electrodes avoid inflammation and structural tissue damage. • Thermoreactive sol–gel enables rapid in-situ fixation at physiological temperature. • Adhesive and conformable interface ensures wrinkle-free TM contact. • Matched mechanical compliance stabilizes coupling during TM micro-vibrations. • Ionic conductivity and low impedance enable high-fidelity signal recording. Electrocochleography (ECochG) provides an objective assessment of cochlear and auditory nerve function and is widely used clinically, particularly during cochlear implant surgery for hearing preservation monitoring. However, ear-canal ECochG recordings remain technically challenging because unstable electrode–tissue contact can compromise signal consistency. Conventional transtympanic electrodes contact the tympanic membrane (TM) through the ear canal but often exhibit limited conformability due to their rigid metallic structure. Although transtympanic ECochG provides high-quality signals, it requires TM penetration and therefore remains invasive. Here, we report a fibrous inner-ear ECochG electrode (ECochGel) that forms a conformal and reversible adhesive interface with the TM, enabling stable recordings without conductive pastes or mechanical fixation. The ECochGel exhibits a mild thermally triggered sol–gel transition and tissue-matched mechanical compliance, resulting in strong interfacial adhesion (60.0 ± 8.0 kPa) and reduced mechanical mismatch (tensile modulus: 13.5 ± 1.4 kPa). Electrochemical characterization shows low interfacial impedance (10.23 ± 0.09 Ω at 1 kHz). In recordings, ECochGel produces lower detection thresholds and larger compound action potential (CAP) amplitudes than commercial electrodes. Histological analysis confirms good biocompatibility with minimal tissue perturbation. These results demonstrate ECochGel as a soft, conformal interface for stable ECochG recording with potential applications in auditory diagnostics and intraoperative monitoring.
Shang et al. (Fri,) studied this question.