Low noise microelectrode array signal headstage pre-amplifier for in-vitro neuron culture

MEA (Micro-Electrode Array) is a very useful device for extracellular signal recording of in-vitro cultured neurons or network of neurons. It can be used for the research of the neuronal network dynamics, recording with the microelectrodes the spontaneous activity signals of the network of neurons, and the evocated physiological signals in response to chemical or electrical stimulations. The electrophysiological signals measured by the microelectrodes are in microvolt order of magnitude, so that these signals should be amplified a factor of 1000 (or 30 dB) by a two-phase amplification system, with special techniques that avoid the amplification of noise. This paper describes the design of a low noise first stage of the MEA signal amplifier, denoted headstage amplifier. The design, simulation and construction of a prototype of the headstage amplifier, and a pass-band filter, are described. The results show the feasibility of the proposal, leading to the construction of a prototype amplification system for the whole MEA with 60 microelectrodes.