Single molecule tracking scheme using a near-field scanning optical microscope
2002; American Institute of Physics; Volume: 73; Issue: 7 Linguagem: Inglês
10.1063/1.1482153
ISSN1527-2400
AutoresR. S. Decca, C.-W. Lee, S. Lall, Stephen R. Wassall,
Tópico(s)Force Microscopy Techniques and Applications
ResumoThe use of a near-field scanning optical microscope (NSOM) to measure the diffusion of fluorescently tagged molecules on a quasi-two-dimensional system is described. The heart of the apparatus lies in the circular motion of the NSOM probe, allowing the detection of small displacements on single molecules. Using a 100 nm tip, and a simulated diffusion coefficient of D∼1×10−12 m2/s, we found that molecules can be tracked within ∼40 nm over several seconds. We foresee that D as large as ∼5×10−12 m2/s can be measured with minor modifications to the experimental setup. These values of D encompass those found in many liquid crystalline systems, particularly lipids in bilayer membranes.
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