title: Single biomolecule imaging with frequency and force modulation in tapping-mode atomic force microscopy.
abstract: A new intermittent-contact atomic force microscopy (AFM) mode (frequency and force modulation AFM, FFM-AFM) has been recently proposed to characterize soft samples. This method uses excitation force frequency and amplitude modulation to eliminate bistability and reduce the tip-sample forces. This letter describes theoretical modeling of FFM-AFM applied to a single bacteriorhodopsin molecule on a substrate, showing that its cross section can be measured without damage, in contrast to conventional tapping-mode AFM. Speculations are made regarding nonideal conditions and the ability of FFM-AFM to perform quantitative nanoelasticity measurements.
authors.forename: Santiago D
authors.initials: SD
authors.lastname: Solares
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry*; D001703:Biophysics / Q000379:methods*; D002627:Chemistry, Physical / Q000379:methods*; D003198:Computer Simulation; D018625:Microscopy, Atomic Force / Q000379:methods*; D008954:Models, Biological; D008958:Models, Molecular; D008962:Models, Theoretical; D037742:Nanotubes, Carbon / Q000737:chemistry; D012984:Software
chemical_list: D037742:Nanotubes, Carbon; D001436:Bacteriorhodopsins