Previous work has shown that it is possible to image whole uncoated chloroplasts using scanning tunneling microscopy (STM), provided this is done in solution using tunnelling currents below about 100 pA.
More recent images include some which suggest that the STM is sensitive to dynamic processes occurring on chloroplast surfaces. Current-versus-distance curves and dI/ds measurements are consistent with tunnelling between the tip and sample surface, and relatively small deformations of the sample surface due to tip-sample forces. Attempts to use the same imaging conditions on bacteria were unsuccessful.
Dahn, Douglas C.; Cake, Katrina; MacDonald, T. Lynn; and Hale, Lawrence R.
"Scanning Tunneling Microscopy Studies of Chloroplasts in Solution,"
Scanning Microscopy: Vol. 9
, Article 10.
Available at: https://digitalcommons.usu.edu/microscopy/vol9/iss2/10