Electrical interfacing between neurons and electronics via vertically integrated sub-4 μm-diameter silicon probe arrays fabricated by vapor–liquid–solid growth

We report here a technique for use in electrical interfaces between neurons and microelectronics, using vertically integrated silicon probe arrays with diameters of 2–3.5 μm and lengths of 60–120 μm. Silicon probe arrays can be fabricated by selective vapor–liquid–solid (VLS) growth. A doped n-type silicon probe with the resistance of 1 kΩ has an electrical impedance of less than 10 MΩ in physiological saline. After inserting the probe arrays into the retina of a carp (Cyrpinus carpio), we conducted electrical recording of neural signals, using the probes to measure light-evoked electrical neural signals. We determined that recorded signals represented local field potentials of the retina (electroretinogram (ERG)). The VLS-probe can provide minimally invasive neural recording/stimulation capabilities at high spatial resolution for fundamental studies of nervous systems. In addition, the probe arrays can be integrated with microelectronics; therefore, these probes make it possible to construct interfaces between neurons and microelectronics in advanced neuroscience applications.