Nucleic Acids Research, Vol 27, Issue 14 2966-2971, Copyright © 1999 by Oxford University Press
KB Thurmond 2nd, EE Remsen, T Kowalewski and KL Wooley
We demonstrate compaction of DNA with nanoscale biomimetic constructs which
are robust synthetic analogs of globular proteins. These constructs are
approximately 15 nm in diameter, shell crosslinked knedel-like (SCKs)
nanoparticles, which are prepared by covalent stabilization of amphiphilic
di-block co-polymer micelles, self- assembled in an aqueous solution. This
synthetic approach yields size- controlled nanoparticles of persistent
shape and containing positively charged functional groups at and near the
particle surface. Such properties allow SCKs to bind with DNA through
electrostatic interactions and facilitate reduction of the DNA hydrodynamic
diameter through reversible compaction. Compaction of DNA by SCKs was
evident in dynamic light scattering experiments and was directly observed
by in situ atomic force microscopy. Moreover, enzymatic digestion of the
DNA plasmid (pBR322, 4361 bp) by Eco RI was inhibited at low SCK:DNA ratios
and prevented when [le]60 DNA bp were bound per SCK. Digestion by Msp I in
the presence of SCKs resulted in longer DNA fragments, indicating that not
all enzyme cleavage sites were accessible within the DNA/SCK aggregates.
These results have implications for the development of vehicles for
successful gene therapy applications.
ARTICLES
Packaging of DNA by shell crosslinked nanoparticles
Department of Chemistry, Washington University, 1 Brookings Drive, St Louis, MO 63130, USA.
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