Three-dimensional helical integration of high-density linear microelectrode arrays and their cross-tissue applications

Implantable neural microelectrodes are the core components enabling high spatiotemporal resolution neural signal recording and stimulation in brain-computer interfaces (BCIs). However, current technologies still face challenges in achieving high-throughput recording, precise implantation, and long-term stability. In this work, we present a high-throughput three-dimensional (3D) helical stretchable neural probe, fabricated via planar electrode micro-fabrication technology followed by thermally driven helical shaping. The main innovations are reflected in the following: First, through the helical deformation, it is possible to simultaneously achieve cross-tissue recording on cortical surface, deep brain, and inside blood vessels. Secondly, the helical structure can expand the wiring space of the electrodes into three dimensions, achieving high spatial resolution and good mechanical compatibility with the tissue. Interface mechanics simulations indicate that the helical structure effectively mitigates strain induced by brain micromotion. Electrochemical modification significantly reduces interface impedance and enhances charge storage capacity (CSC), while cyclic stretching tests confirm stable electrochemical performance under repeated high-strain conditions. Trans-tissue in vivo experiments further validate the probe's versatility: flexible planar MEAs successfully recorded high-quality subcutaneous electromyography (EMG) signals in mice; the helical probe captured single-unit activity in the deep brain of mice with long-term recording stability; and 1024-channel high-throughput signal acquisition was achieved in the pig cerebral cortex. This technology enables high-throughput, stretchable, and cross-scale long-term stable neural recording, providing a versatile tool for next-generation BCIs and clinical neuromonitoring.