Skip to main content
. Author manuscript; available in PMC: 2011 Nov 15.
Published in final edited form as: Methods Enzymol. 2010;475:27–59. doi: 10.1016/S0076-6879(10)75002-3

Scheme 2.1. Schematic showing the key idea of super-resolution imaging of a structure by PALM.

Scheme 2.1

(A) It is not possible to resolve the underlying structure in a conventional widefield fluorescence image because the fluorescent labels are in high concentration and the images overlap. (B) Using controllable fluorophores, it is possible to turn on and image a sparse subset of molecules which then can be localized with nanometer precision (black line is the underlying structure being sampled). Once the first subset of molecules photobleaches, another subset is turned on and localized. This process is repeated and the resulting localizations summed to give a super-resolution image of the underlying structure.