Dols-Perez…Fumagalli {Nanoscale 7: 18327}

Nanoscale electric polarizability of ultrathin biolayers on insulating substrates by electrostatic force microscopy. Nanoscale. 2015 Oct 29;7(43):18327-36.
Topography and dielectric image (capacitance gradient) of a bacteriorhodopsin monolayer patch, 5.3 nm thick on a mica substrate. By combining information from the two images the dielectric constant of the protein layer can be determined with nanoscale lateral spatial resolution