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Simultaneous AFM Manipulation and Fluorescence Imaging of Single DNA Strands
Author(s) -
Hards Andrew,
Zhou Chunqing,
Seitz Markus,
Bräuchle Christoph,
Zumbusch Andreas
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200400515
Subject(s) - force spectroscopy , dna , polylysine , fluorescence , atomic force microscopy , chemistry , biophysics , persistence length , molecule , nanotechnology , fluorescence microscope , single molecule experiment , crystallography , chemical physics , materials science , optics , physics , biochemistry , biology , organic chemistry
We report combined atomic force and far‐field fluorescence microscopic experiments which allow the simultaneous atomic force manipulation and optical observation of individual dye‐labeled DNA molecules. A detailed understanding of the binding properties of DNA to different transparent surfaces is prerequisite for these investigations. Atomic force spectroscopy and fluorescence microscopy of single DNA strands yielded detailed insight into two different types of DNA binding onto transparent polylysine‐coated and silanized glass surfaces. We subsequently demonstrate how the different binding can be exploited to perform two types of nanomanipulation experiments: On polylysine, strong electrostatic interactions over the whole length of the DNA strand enable the writing of micrometer‐sized patterns. By contrast, the strong pointwise attachment of DNA to silanized surfaces allows horizontal stretching of single DNA strands to lengths exceeding 1.6 times the contour length of the DNA strand. With this new approach it is possible to directly observe the rupture of the strongly bonded DNA strand.