Chitosan-DNA complexes: charge inversion and DNA condensation.
Colloids Surf B Biointerfaces
; 114: 1-10, 2014 Feb 01.
Article
de En
| MEDLINE
| ID: mdl-24161501
ABSTRACT
The design of biocompatible polyelectrolyte complexes is a promising strategy for in vivo delivery of biologically active macromolecules. Particularly, the condensation of DNA by polycations received considerable attention for its potential in gene delivery applications, where the development of safe and effective non-viral vectors remains a central challenge. Among polymeric polycations, Chitosan has recently emerged as a very interesting material for these applications. In this study, we compare the observed aggregation behavior of Chitosan-DNA complexes with the predictions of existing models for the complexation of oppositely charged polyelectrolytes. By using different and complementary microscopy approaches (AFM, FESEM and TEM), light scattering and electrophoretic mobility techniques, we characterized the structures of the complexes formed at different charge ratios and Chitosan molecular weight. In good agreement with theoretical predictions, a reentrant condensation, accompanied by charge inversion, is clearly observed as the polycation/DNA charge ratio is increased. In fact, the aggregates reach their maximum size in correspondence of a value of the charge ratio where their measured net charge inverts its sign. This value does not correspond to the stoichiometric 11 charge ratio, but is inversely correlated with the polycation length. Distinctive "tadpole-like" aggregates are observed in excess polycation, while only globular aggregates are found in excess DNA. Close to the isoelectric point, elongated fiber-like structures appear. Within the framework of the models discussed, different apparently uncorrelated observations reported in the literature find a systematic interpretation. These results suggest that these models are useful tools to guide the design of new and more efficient polycation-based vectors for a more effective delivery of genetic material.
Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
ADN
/
Chitosane
/
Électricité statique
Type d'étude:
Prognostic_studies
Limites:
Animals
Langue:
En
Journal:
Colloids Surf B Biointerfaces
Sujet du journal:
QUIMICA
Année:
2014
Type de document:
Article
Pays d'affiliation:
Italie