De Paula Pansani Oliveira, Franciele [UNESP]Picola, Isadora Pfeifer Dalla [UNESP]Shi, QinBarbosa, Hellen Franciane Gonçalves [UNESP]De Oliveira Tiera, Vera Aparecida [UNESP]Fernandes, Júlio CesarTiera, Marcio José [UNESP]2014-05-272014-05-272013-02-08Nanotechnology, v. 24, n. 5, 2013.0957-44841361-6528http://hdl.handle.net/11449/74572Chitosan has been indicated as a safe and promising polycation vector for gene delivery. However its low transfection efficiency has been a challenging obstacle for its application. To address this limitation, we synthesized chitosan derivatives which had increasing amounts of diethylethylamine groups (DEAE) attached to the chitosan main chain. The plasmid DNA VR1412 (pDNA), encoding the ß-galactosidase (ß-gal) reporter gene was used to prepare nanoparticles with the chitosan derivatives, and the transfection studies were performed with HeLa cells. By means of dynamic light scattering and zeta potential measurements, it was shown that diethylethylamine-chitosan derivatives (DEAEx-CH) were able to condense DNA into small particles having a surface charge depending on the polymer/DNA ratio (N/P ratio). Nanoparticles prepared with derivatives containing 15 and 25% of DEAE groups (DEAE15-CH and DEAE25-CH) exhibited transfection efficiencies ten times higher than that observed with deacetylated chitosan (CH). For derivatives with higher degrees of substitution (DS), transfection efficiency decreased. The most effective carriers showed low cytotoxicity and good transfection activities at low charge ratios (N/P). Vectors with low DS were easily degraded in the presence of lysozyme at physiological conditions in vitro and the nontoxicity displayed by these vectors opens up new opportunities in the design of DEAE-chitosan-based nanoparticles for gene delivery. © 2013 IOP Publishing Ltd.engCharge ratioChitosan derivativesDeacetylated chitosansDegrees of substitutionGalactosidasesGene DeliveryHeLa cellIn-vitroMain chainsNon-toxicityPhysiological conditionPlasmid DNAPolycationsReporter geneSmall particlesTransfection activityTransfection efficiencyZeta potential measurementsEfficiencyGene encodingGene transferNanoparticlesZeta potentialChitosanArtigo10.1088/0957-4484/24/5/055101WOS:000313568700002Acesso restrito2-s2.0-848723826118796747160088337