Three-dimensional probe reconstruction for atomic force microscopy

Abstract

Colloidal gold particles are used as hard, spherical imaging targets to assist in the three-dimensional reconstruction of the atomic force probe apex. Probe reconstructions are shown to be accurate to 1 nm resolution and dynamically change as the sample is scanned, emphasizing the utility of colloidal gold particles as in situ calibration standards for image reconstruction of a coadsorbed specimen.

Localization of individual calcium channels at the release face of a presynaptic nerve terminal

“…The apparent particle widths may be larger than 30 nm owing to a convolution of the scanning tip and the particle edges. However, this exaggerated fringe of sharp-edged objects, characteristic of AFM, does not affect the localization of the particle centers (Vasenka et al, 1994).…”

Visualization of Nucleosomal Substructure in Native Chromatin by Atomic Force Microscopy

“…All AFM samples were scanned in less than 10% relative humidity, achieved using a humidity chamber (Bioforce Lab, Ames, IA) perfused with dry N2 gas. Contact mode images were obtained on a Nanoscope I11 AFM (Digital Instruments, Santa Barbara, CA), using oxide-etched silicon nitride tips [200 pm, tip radius 10-20 nm as determined using colloidal gold standards (Vesenka et al, 1993a(Vesenka et al, , 1994] at scan speed 0.2 pmls and sampling forces less than 5 nN. Tapping mode images (Zhong et al, 1993) were obtained on a Nanoscope I11 with a multimode AFM, using Nanoprobe silicon tips (125 pm, tip radius 5-10 nm) at scan speed 1 p d s .…”

Force measurements with the atomic force microscope: Technique, interpretation and applications

“…With a high resolution TEM Chung et al [157] even succeeded to reveal the crystalline structure of a silicon tip. An alternative which does not require an electron microscope is to image a sharp structure and reconstruct the tip shape from the image [153,158,159]. In this case one relies on a defined structure of the sharp object and the characterization itself might cause damage to the tip.…”