Adv Polym Sci (2014) 256: 103–196
DOI: 10.1007/12_2013_218
# Springer-Verlag Berlin Heidelberg 2013
Published online: 16 May 2013
Polyelectrolyte Complexes of DNA and
Polycations as Gene Delivery Vectors
Annabelle Bertin
Abstract This review gives representative examples of the various types of
synthetic cationic polymers or polyampholytes (chemical structure, architecture,
etc) that can be used to complex DNA (forming polyplexes) for their application in
gene delivery. In designing polycations for gene delivery, one has to take into
account a balance between protection of DNA versus loss of efficiency for DNA
condensation and efficient condensation versus hindering of DNA release. Indeed,
if the polyplexes are not stable enough, premature dissociation will occur before
delivery of the genetic material at the desired place, resulting in low transfection
efficiency; on the other hand, a complex that is too stable will not release the DNA,
also resulting in low gene expression. The techniques generally used to determine
these properties are gel electrophoresis to test the DNA/polymer complexation,
ethidium bromide or polyanion displacement to test the affinity of a polymer for
DNA, and light scattering to determine the extent of DNA condensation. Moreover,
with the development of more precise instruments for physico-chemical characterization and appropriate biochemical and biophysical techniques, a direct link
between the physico-chemical characteristics of the polyplexes and their in vitro
and in vivo properties can be drawn, thus allowing tremendous progress in the quest
towards application of polyplexes for gene therapy, beyond the research laboratory.
Keywords Colloidal stabilization Á DNA Á Gene delivery vectors Á Polyampholytes Á
Polycations Á Polyelectrolyte complexes Á Polyplexes
A. Bertin (*)
Division 6.5 “Polymers in Life Science and Nanotechnology”, Federal Institute for Materials
Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany
Department of Biology, Chemistry, and Pharmacy, Freie Universita ¨t Berlin, Takustrasse 3,
14195 Berlin, Germany
e-mail: annabelle.bertin@bam.de
DOI: 10.1007/12_2013_218
# Springer-Verlag Berlin Heidelberg 2013
Published online: 16 May 2013
Polyelectrolyte Complexes of DNA and
Polycations as Gene Delivery Vectors
Annabelle Bertin
Abstract This review gives representative examples of the various types of
synthetic cationic polymers or polyampholytes (chemical structure, architecture,
etc) that can be used to complex DNA (forming polyplexes) for their application in
gene delivery. In designing polycations for gene delivery, one has to take into
account a balance between protection of DNA versus loss of efficiency for DNA
condensation and efficient condensation versus hindering of DNA release. Indeed,
if the polyplexes are not stable enough, premature dissociation will occur before
delivery of the genetic material at the desired place, resulting in low transfection
efficiency; on the other hand, a complex that is too stable will not release the DNA,
also resulting in low gene expression. The techniques generally used to determine
these properties are gel electrophoresis to test the DNA/polymer complexation,
ethidium bromide or polyanion displacement to test the affinity of a polymer for
DNA, and light scattering to determine the extent of DNA condensation. Moreover,
with the development of more precise instruments for physico-chemical characterization and appropriate biochemical and biophysical techniques, a direct link
between the physico-chemical characteristics of the polyplexes and their in vitro
and in vivo properties can be drawn, thus allowing tremendous progress in the quest
towards application of polyplexes for gene therapy, beyond the research laboratory.
Keywords Colloidal stabilization Á DNA Á Gene delivery vectors Á Polyampholytes Á
Polycations Á Polyelectrolyte complexes Á Polyplexes
A. Bertin (*)
Division 6.5 “Polymers in Life Science and Nanotechnology”, Federal Institute for Materials
Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany
Department of Biology, Chemistry, and Pharmacy, Freie Universita ¨t Berlin, Takustrasse 3,
14195 Berlin, Germany
e-mail: annabelle.bertin@bam.de