Next Article in Journal
Hepatoprotective Effects of Ixora parviflora Extract against Exhaustive Exercise-Induced Oxidative Stress in Mice
Next Article in Special Issue
Analysis of Biotinylated Generation 4 Poly(amidoamine) (PAMAM) Dendrimer Distribution in the Rat Brain and Toxicity in a Cellular Model of the Blood-Brain Barrier
Previous Article in Journal
Pyrrolizidine Alkaloids and Fatty Acids from the Endemic Plant Species Rindera umbellata and the Effect of Lindelofine-N-oxide on Tubulin Polymerization
Previous Article in Special Issue
An Azabisphosphonate-Capped Poly(phosphorhydrazone) Dendrimer for the Treatment of Endotoxin-Induced Uveitis
Molecules 2013, 18(9), 10707-10720; doi:10.3390/molecules180910707

DNA Condensation by Partially Acetylated Poly(amido amine) Dendrimers: Effects of Dendrimer Charge Density on Complex Formation

1, 2, 2,3, Jr. 2,3 and 1,*
1 Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA 2 Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, MI 48109, USA 3 Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
* Author to whom correspondence should be addressed.
Received: 1 August 2013 / Revised: 29 August 2013 / Accepted: 30 August 2013 / Published: 3 September 2013
(This article belongs to the Special Issue Dendrimers in Medicine and Biotechnology)
View Full-Text   |   Download PDF [1153 KB, uploaded 18 June 2014]   |   Browse Figures


The ability of poly(amido amine) (or PAMAM) dendrimers to condense semiflexible dsDNA and penetrate cell membranes gives them great potential in gene therapy and drug delivery but their high positive surface charge makes them cytotoxic. Here, we describe the effects of partial neutralization by acetylation on DNA condensation using light scattering, circular dichroism, and single molecule imaging of dendrimer-DNA complexes combed onto surfaces and tethered to those surfaces under flow. We find that DNA can be condensed by generation-five (G5) dendrimers even when the surface charges are more than 65% neutralized, but that such dendrimers bind negligibly when an end-tethered DNA is stretched in flow. We also find that when fully charged dendrimers are introduced by flow to end-tethered DNA, all DNA molecules become equally highly coated with dendrimers at a rate that becomes very fast at high dendrimer concentration, and that dendrimers remain bound during subsequent flow of dendrimer-free buffer. These results suggest that the presence of dendrimer-free DNA coexisting with dendrimer-bound DNA after bulk mixing of the two in solution may result from diffusion-limited irreversible dendrimer-DNA binding, rather than, or in addition to, the previously proposed cooperative binding mechanism of dendrimers to DNA.
Keywords: DNA condensation; dendrimer acetylation; cooperative binding DNA condensation; dendrimer acetylation; cooperative binding
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Share & Cite This Article

Further Mendeley | CiteULike
Export to BibTeX |
EndNote |
MDPI and ACS Style

Yu, S.; Li, M.-H.; Choi, S.K.; Baker, J.R., Jr.; Larson, R.G. DNA Condensation by Partially Acetylated Poly(amido amine) Dendrimers: Effects of Dendrimer Charge Density on Complex Formation. Molecules 2013, 18, 10707-10720.

View more citation formats

Related Articles

Article Metrics

For more information on the journal, click here


[Return to top]
Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert