Magnetically Assisted Minimally Invasive MEMS Flexible Cortical Electrode Array with High Expansion Ratio

We report a silk-based, magnetically assisted MEMS flexible cortical neural interface designed to minimize implantation injury while enabling large-scale electrocorticographic mapping. The system employs a silk-derived magneto-responsive scaffold that guides flexible cortical electrode arrays through a minimally invasive 4-5 mm cranial opening into the subdural space. In vivo experiments demonstrate an approximately 30-fold expansion, representing the highest reported to date. In contrast to conventional methods that rely on passive unfolding driven by tissue interaction and anatomical confinement, this approach enables remote, magnetically controlled active deformation and large-scale conformal deployment across cortical regions. The strategy markedly reduces craniotomy size, mitigates tissue compression and injury, and achieves extensive cortical coverage, yielding abundant neural signals suitable for high-precision decoding in complex behavioral paradigms.