Fig. 4

Nanoscale field-effect transistor electrodes. a Schematic diagram of the free-standing V-shaped nanotransistor electrodes, adapted from ref. [13]. b Schematic diagram of the U-shaped nanotransistor electrode, adapted from ref. [51]. c Branched intracellular nanotube field-effect transistor, reproduced from ref. [55]. d The action potential recordings from a free-standing nanotransistor probe in contact with a cardiomyocyte, being represented as an intracellular recording, reproduced from ref. [50]