Three-Dimensional, Flexible Nanoscale Field-Effect Transistors as Localized Bioprobes

TLDR

Cell potential nanoprobes face design compromises; microelectrodes require hundreds‑nanometer widths to obtain useful signals, whereas nanoscale FETs can be tens of nanometers but typically only measure outer cell potential. The authors fabricated kinked nanowires to produce a sharp probe tip oriented away from the substrate. A phospholipid‑bilayer coating enabled the probe to penetrate beating cardiac cell membranes and track temporal changes in cell potential. Tian et al.

Abstract

Nanoprobes of Cell Potential Direct electrical measurements of cell potentials usually face design compromises. Microelectrodes probe within the cytosol of cells but have a minimum size (hundreds of nanometers in width) for obtaining useful signals. Nanoscale field effect transistors (FETs) can have an active probe size of only tens of nanometers but generally allow only the outer cell potential to be measured. Tian et al. (p. 830 ) fabricated nanowires in which kinks could be introduced to create a sharp probe tip pointing away from the fabrication substrate. Coating the tip with a phospholipid bilayer allowed the probe to be inserted through the membranes of beating cardiac cells, where it could be used to follow temporal changes in cell potential.