Study of insertion characteristics of si neural probe with sharpened tip for minimally invasive insertion to brain

We have fabricated various types of Si neural probe for in vivo and in vitro neuronal signal recordings by combining standard photolithography with a bulk micromachining process. To place the probe tip at target areas in the brain precisely, the mechanical properties of the Si neural probes with various tip shapes were carefully investigated under different insertion conditions to brain phantoms. As results, the minimum length and penetration force of the Si neural probe were determined from conditions where the Si neural probe began to penetrate the surface of the brain phantom. To control buckling of the Si neural probe, it is necessary to optimize the insertion rate in accordance with the conditions of the Si neural probe. Although the insertion forces of the Si neural probe with a sharpened tip were smaller than those of the Si neural probe with a normal tip, the effect of the probe tip shape became small with increased insertion speeds.