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Microcantilever Counter Electrode Electrochemical Sensor in a Three-Electrode Cell

Oak Ridge National Laboratory

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Technology Marketing SummaryResearchers at ORNL have invented a compact, highly accurate system to detect
and measure chemicals in solution. The device can be used to detect ions and other
electroactive species, hostile biological agents, and protein fragments. The device is
a three-electrode cell in which the counter electrode is a microcantilever. The entire
sensor (or an array of sensors) could be fabricated as an integrated circuit on a silicon

DescriptionThe microcantilever’s extreme sensitivity makes it an excellent chemical and
biochemical sensor. In this invention, the cantilever is made conductive and chemically
selective by coating one surface with a metal. The three-electrode configuration
overcomes the limitations of previous designs, in which the cantilever is also the
working electrode, by separating the sensor from the reactions at the working

Piezoresistance causes the cantilever to bend when current is applied to it. The
presence of chemicals adhered to its surface affects the extent of its deflection.
Chemicals are identified by the effect that they have on the cantilever’s deflection,
as determined by changes in resistance and in the angle of reflection of a laser beam
trained on the cantilever’s surface.
  • Handles very small sample volumes
  • Extremely sensitive and selective
  • Tunable by varying the dopant applied to the cantilever
  • Built with established semiconductor fabrication techniques

Applications and Industries
  • Detect ions or other electroactive species
  • Detect hostile biological agents
  • Detect protein fragments
  • Use as a detector for scanning tunneling microscopy
  • Aid understanding of double layers or diffusion layers in electrolyte solutions
  • Mechanical ammeter in electrochemical cells
  • Water quality analysis

More InformationPatent
Thomas G. Thundat and Gilbert M. Brown, Electrochemical Sensor Having Suspended Element Counter Electrode and Deflection Method for Current Sensing, U.S. Patent 7,716,965, issued May 18, 2010.

Thomas G. Thundat and Gilbert M. Brown
Biosciences Division
Chemical Sciences Division
Oak Ridge National Laboratory
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 7,716,965
Electrochemical sensor having suspended element counter electrode and deflection method for current sensing
An electrochemical suspended element-based sensor system includes a solution cell for holding an electrolyte comprising solution including at least one electrochemically reducible or oxidizable species. A working electrode (WE), reference electrode (RE) and a counter electrode (CE) are disposed in the solution. The CE includes an asymmetric suspended element, wherein one side of the suspended element includes a metal or a highly doped semiconductor surface. The suspended element bends when current associated with reduction or oxidation of the electrochemically reducible or oxidizable species at the WE passes through the suspended element. At least one measurement system measures the bending of the suspended element or a parameter which is a function of the bending.
Oak Ridge National Laboratory 05/18/2010
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated

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To: Nestor Fronco<>