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The fractal structure of polycation–DNA complexes
Author(s) -
Sarkar Supti,
Lee Li Kim,
Hart Stephen L.,
Hailes Helen C.,
Levy Susana M.,
Tabor Alethea,
Shamlou Parviz Ayazi
Publication year - 2005
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1042/ba20040017
Subject(s) - fractal dimension , fractal , chemical physics , colloid , ionic strength , dynamic light scattering , suspension (topology) , chemistry , materials science , nanotechnology , biological system , biophysics , nanoparticle , biology , mathematics , aqueous solution , mathematical analysis , homotopy , pure mathematics
We used static light scattering to obtain new measurements on the internal structure of aggregated non‐viral gene‐delivery particles in colloidal suspension. The vector particles are prepared by charge neutralization of plasmid DNA either by poly‐ l ‐lysine or by a Lipofectin/integrin‐targeting peptide. We use established theories of the stability of colloidal particles and fractal concepts to explain the aggregation processes and demonstrate the existence of a new property (fractal dimension) of the aggregated vector particles. Aggregation is shown to produce particles with fractal dimensions in the range between 1.8 and 2.4; the former suggests a loose three‐dimensional structure and the latter characterizes an aggregation process that leads to the formation of particles with tightly packed structures. We show that the fractal dimension of the vector particles is sensitive to changes in physicochemical conditions (ionic strength) of the buffer solution and propose that fractal dimension may provide a useful means of monitoring the physical state of non‐viral delivery‐vector particles during preparation and storage.