Recording of cell action potentials with AlGaN∕GaN field-effect transistors

An $\mathrm{Al}\mathrm{Ga}\mathrm{N}∕\mathrm{Ga}\mathrm{N}$ electrolyte gate field-effect transistor array for the detection of electrical cell signals has been realized. The low-frequency noise power spectral density of these devices exhibits a $1∕f$ characteristic with a dimensionless Hooge parameter of $5\times {10}^{-3}$ . The equivalent gate-input noise under operation conditions has a peak-to-peak amplitude of $15\mu \mathrm{V}$ , one order of magnitude smaller than for common silicon-based devices used for extracellular recordings. Extracellular action potentials from a confluent layer of rat heart muscle cells cultivated directly on the nonmetallized gate surface were recorded with a signal amplitude of $75\mu \mathrm{V}$ and a signal-to-noise ratio of 5:1.