BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Volume, Number, Page
Vol. 231
No. 3
pp. 566-569
Published date
Feb. 1997
Publisher
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English:
Academic Press
Conference name
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Conference site
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Abstract
We refined scanning probe force microscopy to improve the sensitivity of force detection and control of probeposition. Force sensitivity was increased by incorporatinga cantilever with very low stiffness, 0.1pN/nm, which is over 1000-fold more flexible than is typically used in conventional atomic force microscopy. Thermal bending motions of the cantilever were reduced to less than 1 nm by exerting feed-back positioning with laser radiation pressure. The system was tested by measuring electrostatic repulsive forces or hydrophobic attractive forces in aqueous solutions. Subpiconewton intermolecular forces were resolved at controlled gaps in the nanometer range between the probe and a material surface. These levels of force and position sensitivity meet the requirements needed for future investigations of intermolecular forces between biological macromolecules such as proteins, lipids and DNA.