On-chip electroporation, membrane repair dynamics and transient in-cell recordings by arrays of gold mushroom-shaped microelectrodes

This study demonstrates the use of on-chip gold mushroom-shaped microelectrodes (gM mu Es) to generate localized electropores in the plasma membrane of adhering cultured neurons and to electrophysiologically monitor the ensuing membrane repair dynamics. Delivery of an alternating voltage pulse (0.5-1 V, 100 Hz, 300 ms) through an extracellularly positioned micrometer-sized gM mu E electroporates the patch of plasma membrane facing the microelectrode. The repair dynamics of the electropores were analyzed by continuous monitoring of the neuron transmembrane potential, input resistance (R-in) and action potential (AP) amplitude with an intracellular microelectrode and a number of neighbouring extracellular gM mu Es. Electroporation by a gM mu E is associated with local elevation of the free intracellular calcium concentration ([Ca2+](i)) around the gM mu E. The membrane repair kinetics proceeds as an exponential process interrupted by abrupt recovery steps. These abrupt events are consistent with the membrane patch model of membrane repair in which patches of intracellular membrane fuse with the plasma membrane at the site of injury. Membrane electroporation by a single gM mu E generates a neuron-gM mu E configuration that permits recordings of attenuated intracellular action potentials. We conclude that the use of on-chip cultured neurons via a gM mu E configuration provides a unique neuroelectronic interface that enables the selection of individual cells for electroporation, generates a confined electroporated membrane patch, monitors membrane repair dynamics and records attenuated intracellular action potentials.