AlGaN/GaN-based HEMTs for electrical stimulation of neuronal cell cultures

Abstract

Unipolar source drain voltage pulses of GaN/AlGaN-High Electron Mobility Transistors (HEMT) were used for stimulation of cultured neuronal networks obtained from embryonic rat cerebral cortex. The HEMT sensor was grown by metal organic vapour phase epitaxy on 2 inch sapphire substrate consisting of 10 single HEMTs concentrically arranged around the wafer center. Electrolytic reactions between the HEMT sensor surface and the culture medium were not detected by using cyclic voltammetry. During voltage pulses and resulting neuronal excitation, capacitances were recharged giving indications of the contributions of the AlGaN and the AlOx isolation layers between the two dimensional electron gas (2DEG) channel and the neuron culture. The resulting threshold current for stimulation of neuron activity strongly depends on the culture and HEMT position on the sensor surface under consideration which is caused by different impedances of each neuron culture and position within the culture. The differences of culture impedances can be explained by variations of composition, thickness, and conductivity of the culture areas.

AlGaN/GaN-based biosensor for label-free detection of biological activity

“…However, the strength of the recorded signal was only in the range of tens to hundreds of microvolts [10][11][12]. These devices employed a reference electrode as part of the measurement set up.…”