Nanowire arrays for neuron recordings

Student: Dalmau Reig-i-Plessis
Department: Physics
Advisor: Latika Menon

Abstract

Microelectrode arrays are able to simultaneously record impulses from several different neurons by sensing the minute changes in potential in the medium the cells are in. Since released ions dissipate in the medium, the total change in potential in the medium around the cell is around 30uV. Patch clamp measurements on the other hand are applied directly to a single cell, but have a much higher signal. The patch clamp is placed directly on a cell and is able to measure either the activity of a single sodium potassium pump or measure the activity of the whole cell by measuring the difference between inside and outside the cell membrane. Patch clamp measurements are in the range of 70mV. Although patch clamping is a very effective way of getting precise measurements on a neuron, the measurement will sometimes kill the cell and the apparatus, a thin glass pipette must be carefully placed directly on the cell. This makes prolonged measurements difficult if not impossible and simultaneous measurements on many cells impossible.
This project aims to combine the signal strength of patch clamp measurements with the versatility of having many sensing points of the microelectrode array using gold nanowires. The nanowires will penetrate the cells and approximate the effect of patch clamp measurements, and the wires themselves will be grown on a microelectrode array giving the device the capability of measuring several cells at once. Signal strength is not the only advantage of this geometry; the direct contact with the cell will make it impossible for two channels to pick up the same neuron firing, and therefore gives much greater spatial resolution than microelectrode arrays. Such a device will be able to perform long term, precise measurements on neurons grown directly on the device.