Brain-Adhesive Bioelectronics With Shape-Morphable and Biodegradable Properties for Stable Brain Signal Monitoring

Abstract

Accurate and temporary monitoring of brain activity is essential for diagnosing and treating neurological diseases. Conventional nondegradable electrocorticogram (ECoG) devices require removal surgery, thus increasing the risk of infection and tissue damage. Moreover, existing devices typically fail to conform to soft, dynamic brain tissue, thus resulting in unsatisfactory adhesion, signal loss, and mechanical mismatch. Herein, we present the development of a brain-adhesive sensor (B-Sensor) with shape-morphable and biodegradable characteristics, enabling stable ECoG signal monitoring within a clinically feasible window for patient application. The B-Sensor is fabricated on a polyurethane elastomer incorporated with polycarbonate, which possesses a low glass transition temperature and dynamic bonding, thereby providing biodegradability, stretchability, stress relaxation, and even self-healing capabilities. A tissue-adhesive hydrogel in the B-Sensor ensures conformal cortical adhesion, whereas ultrathin molybdenum electrodes in an open-mesh layout maintain stable performance under cyclic strain and minimize magnetic resonance imaging (MRI) artifacts. The device degrades naturally under physiological conditions, retains impedance stability during use, and exhibits excellent cell viability. In vivo experiments show that the B-Sensor reliably records baseline activity, somatosensory evoked potentials, and 4-aminopyridine-induced epileptiform discharges with high precision. This study demonstrates a bioresorbable, tissue-adhesive ECoG platform that enables safe, artifact-free monitoring of both normal and pathological brain activity, thus offering a new design paradigm for next-generation implantable bioelectronics.