title: DNA/chitosan electrostatic complex.
abstract: Up to now, chitosan and DNA have been investigated for gene delivery due to chitosan advantages. It is recognized that chitosan is a biocompatible and biodegradable non-viral vector that does not produce immunological reactions, contrary to viral vectors. Chitosan has also been used and studied for its ability to protect DNA against nuclease degradation and to transfect DNA into several kinds of cells. In this work, high molecular weight DNA is compacted with chitosan. DNA-chitosan complex stoichiometry, net charge, dimensions, conformation and thermal stability are determined and discussed. The influence of external salt and chitosan molecular weight on the stoichiometry is also discussed. The isoelectric point of the complexes was found to be directly related to the protonation degree of chitosan. It is clearly demonstrated that the net charge of DNA-chitosan complex can be expressed in terms of the ratio [NH3(+)]/[P(-)], showing that the electrostatic interactions between DNA and chitosan are the main phenomena taking place in the solution. Compaction of DNA long chain complexed with low molar mass chitosan gives nanoparticles with an average radius around 150nm. Stable nanoparticles are obtained for a partial neutralization of phosphate ionic sites (i.e.: [NH3(+)]/[P(-)] fraction between 0.35 and 0.80).
authors.affiliation: Universidad de Guadalajara, Departamento de Ingeniería Química, Blvd. M. García Barragán #1451, C.P. 44430 Guadalajara, Jalisco, Mexico; Grenoble Alpes University, LRP, F-38000 Grenoble, France. Electronic address: monik_ayanami@hotmail.com.
authors.forename: Lourdes Mónica
authors.initials: LM
authors.lastname: Bravo-Anaya
authors.affiliation: Universidad de Guadalajara, Departamento de Ingeniería Química, Blvd. M. García Barragán #1451, C.P. 44430 Guadalajara, Jalisco, Mexico. Electronic address: jfasm@hotmail.com.
authors.forename: J F Armando
authors.initials: JF
authors.lastname: Soltero
authors.affiliation: Biomaterials Applications, 6 Rue Lesdiguières, 38000 Grenoble, France. Electronic address: marguerite.rinaudo@sfr.fr.
authors.forename: Marguerite
authors.initials: M
authors.lastname: Rinaudo
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D002417:Cattle; D048271:Chitosan / Q000737:chemistry*; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000302:isolation & purification; D055664:Electrochemical Techniques; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011522:Protons; D055672:Static Electricity; D014162:Transfection
chemical_list: D011522:Protons; D004247:DNA; D048271:Chitosan; C427203:calf thymus DNA
keywords: Chitosan; Compaction; DNA; Electrostatic interactions; Stability