Chitosan-based vector/DNA complexes for gene delivery: biophysical characteristics and transfection ability.
OBJECTIVE
Chitosan, a natural cationic polysaccharide, is a candidate non-viral vector for gene delivery. With the aim of developing this system, various biophysical characteristics of chitosan-condensed DNA complexes were measured, and transfections were performed.


METHODS
Transmission electronic microscopy (TEM) visualizations, sedimentation experiments, dynamic light scattering (DLS), and zeta potential measurements were realized. Transfections were made by using the luciferase reporter gene.


RESULTS
In defined conditions, plasmid DNA formulated with chitosan produced homogenous populations of complexes which were stable and had a diameter of approximately 50-100 nm. Discrete particles of nicely condensed DNA had a donut, rod, or even pretzel shape. Chitosan/DNA complexes efficiently transfected HeLa cells, independently of the presence of 10% serum, and did not require an added endosomolytic agent. In addition, gene expression gradually increased over time. from 24 to 96 hours, whereas in the same conditions the efficacy of polyethylenimine-mediated transfection dropped by two orders of magnitude. At 96 hours, chitosan was found to be 10 times more efficient than PEI. However, chitosan-mediated transfection depended on the cell type. This dependency is discussed here.


CONCLUSIONS
Chitosan presents some characteristics favorable for gene delivery, such as the ability to condense DNA and form small discrete particles in defined conditions.
Laboratoire de Chimie Génétique, CNRS UMR 7514, Faculté de Pharmacie, Université Louis-Pasteur de Strasbourg, Illkirch, France.
P
P
Erbacher
S
S
Zou
T
T
Bettinger
A M
AM
Steffan
J S
JS
Remy
D001704:Biopolymers / Q000235:genetics; D002686:Chitin / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D048271:Chitosan; D004247:DNA / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D037102:Lectins / Q000378:metabolism; D011094:Polyethyleneimine / Q000378:metabolism; D014162:Transfection
D001704:Biopolymers; D037102:Lectins; D002686:Chitin; D011094:Polyethyleneimine; D004247:DNA; D048271:Chitosan