TY - JOUR
T1 - Atomic force microscopy of DNA and bacteriophage in air, water and propanol
T2 - The role of adhesion forces
AU - Lyubchenko, Y. L.
AU - Oden, P. I.
AU - Lampner, D.
AU - Lindsay, Stuart
AU - Dunker, K. A.
N1 - Funding Information:
We are grateful to Zhifeng Shao and Jie Yang for many interesting discussions and for showing us reference 20 prior to its submission. Helen Hansma shared reference 14 with us prior to publication. We have benefited from useful discussions with Lyuda Shlyakhtenko and Rodney Harrington. James Vesenka provided useful comments on the manuscript. Rodney Harrington also provided support to one of us (YL) during periods spent at the University of Nevada, Reno. The work was supported by grants DIR8920053 from the NSF and N0001491J1455 from the ONR. Y.L. is on leave from the Institute of Molecular Genetics of the Russian Academy of Sciences.
PY - 1993/3/11
Y1 - 1993/3/11
N2 - We have developed a chemical treatment for the mica surface which allows blopolymers to be held in place for atomic force microscopy, even under water, using conventional, untreated force sensing tips. We illustrate the procedure with images of σ DNA and fd phage. The phage adheres well enough to permit in situ imaging of the adsorption process in water. These experiments yield a mean length for the phage of 883±72nm. This compares with a measured length of 883±33nm when the phage are imaged after drying following adsorption from water, showing that the effect of dehydration is quite small. Adhesion forces between the force sensing tip and the substrate and the sensing tip and the blomolecules are very different in the three media (air, water and propanol). The apparent height of the phage and the width and height of the DNA depends upon these adhesion forces quite strongly. In contrast, changing the Hookean spring force exerted by the scanning tip makes little difference. These results suggest that the chemical factors involved in adhesion can dominate atomic force images and that the composition of the scanning tip is at least as important a factor as its geometry.
AB - We have developed a chemical treatment for the mica surface which allows blopolymers to be held in place for atomic force microscopy, even under water, using conventional, untreated force sensing tips. We illustrate the procedure with images of σ DNA and fd phage. The phage adheres well enough to permit in situ imaging of the adsorption process in water. These experiments yield a mean length for the phage of 883±72nm. This compares with a measured length of 883±33nm when the phage are imaged after drying following adsorption from water, showing that the effect of dehydration is quite small. Adhesion forces between the force sensing tip and the substrate and the sensing tip and the blomolecules are very different in the three media (air, water and propanol). The apparent height of the phage and the width and height of the DNA depends upon these adhesion forces quite strongly. In contrast, changing the Hookean spring force exerted by the scanning tip makes little difference. These results suggest that the chemical factors involved in adhesion can dominate atomic force images and that the composition of the scanning tip is at least as important a factor as its geometry.
UR - http://www.scopus.com/inward/record.url?scp=0027221946&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027221946&partnerID=8YFLogxK
U2 - 10.1093/nar/21.5.1117
DO - 10.1093/nar/21.5.1117
M3 - Article
C2 - 8464697
AN - SCOPUS:0027221946
SN - 0305-1048
VL - 21
SP - 1117
EP - 1123
JO - Nucleic acids research
JF - Nucleic acids research
IS - 5
ER -