Atomic force microscopy reconstruction of G‐wire DNA

Abstract

<p>A fundamental problem in atomic force microscopy (AFM) image interpretation is distinguishing features arising from tip geometry from true molecular detail. In this study, a novel 4‐stranded form of DNA (the ‘‘G wire’’) was coadsorbed with 7.6‐nm‐diam colloidal gold probe calibration standards and examined by AFM. After the probe apices were reconstructed from AFM images of the standards, the artificial broadening of the coadsorbed G‐wire DNA was removed, resulting in more reliable image interpretation. Using simple geometric models, a favorable comparison between observed and modeled G‐wire cross sections suggests that reconstructions removed about 25% of the tip‐broadened AFMimage in these studies.</p>