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Quantitative manipulation of DNA and viruses with the nanomanipulator scanning force microscope
Author(s) -
Guthold M.,
Matthews G.,
Negishi A.,
Taylor R. M.,
Erie D.,
Brooks F. P.,
Superfine R.
Publication year - 1999
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/(sici)1096-9918(199905/06)27:5/6<437::aid-sia505>3.0.co;2-n
Subject(s) - cantilever , microscope , magnetic force microscope , substrate (aquarium) , materials science , nanotechnology , magnetic field , optics , optoelectronics , physics , composite material , oceanography , magnetization , quantum mechanics , geology
The nanoManipulator, a modified scanning force microscope with adirect manipulation interface that allows natural and controlledmanipulation of nanometer‐sized samples, was used toinvestigate DNA and adenoviruses. During a manipulation, the scanningtip is coupled to a hand‐held stylus via aforce‐feedback loop. Accordingly, the tip follows the movementof the user's hand; moreover, the user is able to feel thetopography of the sample. For imaging fragile biological samples, amagnetically driven intermittent contact (MDIC) mode influid was implemented and added to the microscope. In this mode, acantilever with a magnetic particle glued onto its back is driven byan external, oscillating magnetic field. In contrast to regularintermittent contact (tapping) mode imaging in liquids,where the whole liquid cell is excited (resulting in manyresonance peaks in the spectrum), in this mode the cantilever isdriven directly and the spectrum usually displays a single, easilyidentifiable resonance peak. Using this set‐up, adenoviruseswere manipulated in liquids and 1100 bp DNA molecules weremanipulated in ambient conditions while recording lateral force data.In these experiments, the rupture force of DNA was measured directlyfor the first time. In an effort to measure the interaction forcebetween a virus and a substrate, adenoviruses were pushed over asilicon substrate. A force of ∽25 nN was measured to move thevirus on this surface. Copyright © 1999 John Wiley & Sons,Ltd.