Adapting the Quesant Nomad atomic force microscope for biology and patch-clamp atomic force microscopy.
The Quesant Nomad atomic force microscope (AFM) was modified to produce a reliable patch-clamp AFM for demanding biologic applications. The AFM's laser optics forms the basis of a condenser that allows simultaneous Köhler illumination and AFM imaging on an inverted optical microscope. The original AFM scan head was replaced with plastic and glass to make it biologically inert. A bevel cut in the new scan head permits clearance for patch clamp pipets. Cantilevers are attached to the scan head with a quick setting silicone rubber that is readily removable. Software was developed to (a) automate a gentle approach and set a specific feedback force, (b) provide a mouse-driven control of the X-Y position of the probe tip and recall of saved locations, and (c) measure force-distance curves over user defined paths. Additional modifications were made to minimize mechanical noise. The patch-clamp AFM achieves 600 fA (3 kHz bandwidth) and 1 A RMS noise levels (10 kHz bandwidth). The correlation of electrical and mechanical information allows signal averaging and measures sub-Angstrom, sub-millisecond electromotile responses from cells.
Besch
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Huges Center for Single Molecule Biophysics, Physiology and Biophysical Sciences, SUNY at Buffalo, Buffalo, NY 14214, USA.
Snyder
K V
KV
Zhang
P C
PC
Sachs
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F
D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D018625:Microscopy, Atomic Force / Q000295:instrumentation*; D008858:Microscopy, Phase-Contrast / Q000295:instrumentation; D036103:Nanotechnology; D018408:Patch-Clamp Techniques / Q000295:instrumentation*