Electrolyte-gated graphene field-effect transistors for detecting pH and protein adsorption

Nano Lett. 2009 Sep;9(9):3318-22. doi: 10.1021/nl901596m.


We investigated electrolyte-gated graphene field-effect transistors (GFETs) for electrical detecting pH and protein adsorptions. Nonfunctionalized single-layer graphene was used as a channel. GFETs immersed in an electrolyte showed transconductances 30 times higher than those in a vacuum and their conductances exhibited a direct linear increase with electrolyte pH, indicating their potential for use in pH sensor applications. We also attempted to direct surface-protein adsorption and showed that the conductance of GFETs increased with exposure to a protein at several hundred picomolar. The GFETs thus acted as highly sensitive electrical sensors for detecting pH and biomolecule concentrations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Animals
  • Cattle
  • Electric Capacitance
  • Electric Conductivity
  • Electrodes
  • Electrolytes / chemistry
  • Graphite / chemistry*
  • Hydrogen-Ion Concentration
  • Materials Testing
  • Nanotechnology / instrumentation*
  • Nanotechnology / methods
  • Particle Size
  • Serum Albumin, Bovine / chemistry*
  • Surface Properties
  • Time Factors


  • Electrolytes
  • Serum Albumin, Bovine
  • Graphite