Nanopillar intracellular electrode (nanostraw / gold mushroom)

A family of vertical nanostructures, including protruding nanopillars, mushroom-shaped gold caps, hollow nanostraws, and nanotubes, engineered so a cell will engulf, wrap, or be permeated by the electrode, dramatically raising the seal resistance and coupling. When the membrane is also porated (spontaneously, by electroporation, or by optoporation), these devices achieve transient intracellular-quality recordings, capturing sub-threshold potentials and attenuated action-potential waveforms, with a nominally extracellular, scalable array.

This is a leading route to combine the fidelity of intracellular recording with the parallelism of microelectrode arrays, and has been demonstrated convincingly in vitro (neuronal cultures, cardiomyocytes). The frontier challenge is doing it in vivo and chronically: membranes reseal within minutes to hours, tissue micromotion disrupts the tight junction, and maintaining the intimate seal beyond transient windows in living brain remains unsolved.