A penetrating micro-scale diameter probe array for in vivo neuron spike recordings

We report a 8-12-μm-diameter 210-μm-length penetrating silicon probe array assembled by vapor-liquid-solid (VLS) growth, for use in multi-site recordings of neuron spikes in a brain cortex. A 3-μm-diameter silicon probe-tip metalized with platinum (Pt)-black by the electroplating, exhibits low enough probe impedance of 103 kΩ and a more than 90% output/input ratio (1 kHz) for spike recordings. Through an in vivo neural recording on the barrel cortex of a rat, the probe was able to be penetrated into the cortex, and evoked neuron spikes were detected with the probes. The micro-scale diameter spike detecting probe array is expected to further improve current electrophysiological technique capabilities by together its advantages of the tiny probe geometry and the ability to increase the density of probes.