Switchable Cortical Interfaces with Ion-Mediated Adhesion for In Vivo Seizure Mapping.

Abstract

Precise intraoperative localization of epileptic foci requires neural electrodes that conform tightly to soft brain tissue while remaining removable without inducing tissue damage. However, existing flexible electrodes typically exhibit either insufficient adhesion, resulting in unstable signal acquisition, or irreversible bonding that risks cortical injury upon removal. Here, a Zn² ⁺-regulated, reversibly adhesive flexible cortical electrode based on imidazole-functionalized polydimethylsiloxane (PDMS-IM) is presented. Hydroxyl groups distributed along the polymer backbone provide robust interfacial adhesion to neural tissue and metal electrodes, while terminal imidazole moieties enable reversible coordination with Zn² ⁺ ions. This coordination mechanism allows the electrode to maintain firm, conformal contact during electrophysiological recording and to detach rapidly and cleanly upon Zn² ⁺ exposure without leaving residue on the brain surface. The PDMS-IM elastomer exhibits tunable mechanical properties (modulus of 10-200 kPa), high stretchability, and low interfacial impedance, supporting stable cortical interfacing. In vivo epilepsy models demonstrate that Zn² ⁺-triggered detachment preserves both electrode integrity and cortical surface morphology while enabling reliable multichannel seizure monitoring. By decoupling strong tissue adhesion from atraumatic removal, this work establishes a controllable adhesive interface for transient neural implants and provides a practical strategy for safe cortical mapping in epilepsy surgery and related neurosurgical applications.