Implantable, microfiber neuroelectrodes fabricated out of polycrystalline diamond and boron-doped diamond

This abstract presents micromachined, implantable, all diamond microfibers to facilitate reliable, precision recording of extracellular biopotentials and neurotransmitter concentrations in neural networks (Fig. 1). Each of such microfibers consists of a conductive boron-doped polycrystalline diamond (BDD) core encapsulated in a thin insulating polycrystalline diamond (PCD) cladding. The BDD core enables single-unit recording and neurotransmitter sensing from target neurons with high spatiotemporal resolution and fidelity, while the PCD encapsulation serves as a biocompatible and hermetic package as well as a dielectric barrier to prevent signal cross-talking. The fully developed fibers had been successfully tested ex vivo in different chemicals under different concentrations.