Tip-radius-induced artifacts in AFM images of protamine-complexed DNA fibers.

TitleTip-radius-induced artifacts in AFM images of protamine-complexed DNA fibers.
Publication TypeJournal Article
Year of Publication1992
AuthorsAllen, MJ, Hud, NV, Balooch, M, Tench, RJ, Siekhaus, WJ, Balhorn, R
JournalUltramicroscopy
Volume42-44 ( Pt B)
Pagination1095-100
Date Published1992 Jul
ISSN0304-3991
KeywordsAnimals, Artifacts, Cell Nucleus, Chromatin, DNA, Male, Mice, Microscopy, Protamines, Specimen Handling, Spermatozoa
Abstract

Isolated DNA fibers complexed with protamine (the chromosomal protein that packages DNA in mammalian sperm) have been produced by partially decondensing the highly compacted mouse sperm chromatin particle on a glass coverslip. These DNA fibers were then scanned with the atomic force microscope (AFM). While the smallest of the fibers appear in AFM images as ribbon-like structures 250-350 A wide and 10-25 A high, experiments indicate that these images are the result of a convolution of the imaging-tip's shape with the object's actual shape. In such convolutions the height of the object is affected only by the compressibility of the object, while the width is affected in addition by the sharpness of the tip. Images of polyamidoamine particles also appear to show this artifact. We have also deduced the tip's radius of curvature from images of sharp steps and attempt to demonstrate the artifacts associated with a relatively large imaging tip.

Alternate JournalUltramicroscopy
PubMed ID1413246