Innovation and Partnerships Office

Low Damping Force Sensor for Operation in Liquids IB-3051


  • Atomic force microscopy in the fields of: biology / biotechnology / biomedical research, pharmaceutical development, material sciences, nanofabrication
  • Micro-electrical mechanical systems (MEMS) sensors


  • Increased sensitivity
  • Overcomes limitations of atomic force microscopy for biomedical research
  • Operates, unmodified, with any commercially available atomic force microscope (AFM)


Scientists at Berkeley Lab have invented a low damping force sensor for operation in liquid. The resonator moves independently of an encasement, and a probe attached to the resonator protrudes from the encasement and interacts with the environment. Atomic Force Microscopes (AFMs) are the intended application, but the design may work well to reduce the intrinsic noise of micro-electrical mechanical systems (MEMS) sensors to increase their sensitivity.

For measurements in solution, this arrangement reduces damping losses and yields a higher resonance frequency. The low force noise associated with the low damping expands the possibility of performing measurements in solution, whether imaging a soft material surface as an Atomic Force Microscope (AFM); binding an analyte as a mass sensor; or probing viscosity with higher precision.

Until now, using AFMs to measure the surface of soft materials, such as living cells, has been difficult because the minimum detectable force required, associated with the resonator’s damping losses in solution, can deform the living cells under study, thus reducing resolution and potentially damaging the specimen.

Researchers have been trying to decrease viscous damping in AFM by reducing cantilever size, but too small a size can limit deflection detection sensitivity.  Enclosing the resonator to keep it dry has yielded enclosures so large that any gains from lower viscosity are offset. The Berkeley Lab encased AFM cantilever overcomes shortcomings encountered in earlier attempts and opens up the use of AFMs in biomedical and other research involving samples in solution or living cells.

DEVELOPMENT STAGE:  Proven principle.

STATUS: Issued U. S. Patent 9229028. Available for licensing or collaborative research.


Optimized Carbon Nanotube Tip for AFMs, IB-2793

Study and Modification of Surface Properties with an Atomic Force Microscope, JIB-2653