The team achieved 3-nanometer resolution by controlling the conductivity of the solution. The work paves the way to nanoscale piezo-response force microscopy of biomolecular systems. Recent advances in electromechanical imaging in liquid environments by researchers at the Department of Energy's Oak Ridge National Laboratory are paving the way to new analytical tools for the biological research community.
The work for the first time demonstrates that piezo-response-force imaging is possible in aqueous and other liquid environments, a key step in developing this technique for applications in soft condensed matter and biological systems. Aqueous environments, required for living cells, were believed to be incompatible with electromechanical imaging because the electrically conductive liquid interferes with tip biasing and surface vibration detection and dampens the probe's cantilever. The ORNL team overcame the problem by using high-frequency biases to probe the sample surface, which reduces both the damping effect and interference of liquid conductance.