Electromechanical Imaging of Biological Systems with Sub-10 nm   Resolution
  Electromechanical imaging of tooth dentin and enamel has been performed with sub-10 nm resolution using piezoresponse force microscopy. Characteristic piezoelectric domain size and local protein fiber ordering in dentin have been determined. The shape of a single collagen fibril in enamel is visualized in real space and local hysteresis loops are measured. Because of the ubiquitous presence of piezoelectricity in biological systems, this approach is expected to find broad application in high-resolution studies of a wide range of biomaterials. 
Sergei V. Kalinin, B.J. Rodriguez, S. Jesse, T. Thundat, and A.   Gruverman