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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Effect of ionic strength solution on the stability of chitosan-DNA nanoparticles

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Author(s):
Dalla Picola, Isadora Pfeifer [1] ; Nunes Busson, Karen Andressa [2] ; Case, Ana Helena [1] ; Nasario, Fabio Domingues [2] ; de Oliveira Tiera, Vera Aparecida [2] ; Taboga, Sebastiao Roberto [3] ; Ruggiero Neto, Joao [1] ; Tiera, Marcio Jose [2]
Total Authors: 8
Affiliation:
[1] Sao Paulo State Univ UNESP, Inst Biosci Humanities & Exact Sci IBILCE, Dept Phys, Sao Paulo - Brazil
[2] Sao Paulo State Univ UNESP, Inst Biosci Humanities & Exact Sci IBILCE, Dept Chem & Environm Sci, Sao Paulo - Brazil
[3] Sao Paulo State Univ UNESP, Inst Biosci Humanities & Exact Sci IBILCE, Dept Biol, Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Journal of Experimental Nanoscience; v. 8, n. 5, p. 539-552, JUL 1 2013.
Web of Science Citations: 0
Abstract

ChitosanDNA nanoparticles employed in gene therapy protocols consist of a neutralised, stoichiometric core and a shell of the excess of chitosan which stabilises the particles against further coagulation. At low ionic strength, these nanoparticles possess a high stability; however, as the ionic strength increases, it weakens the electrostatic repulsion which can play a decisive part in the formation of highly aggregated particles. In this study, new results about the effect of ionic strength on the colloidal stability of chitosanDNA nanoparticles were obtained by studying the interaction between chitosans of increasing molecular weights (5, 10, 16, 29, 57 and 150kDa) and calf thymus DNA. The physicochemical properties of polyplexes were investigated by means of dynamic light scattering, static fluorescence spectroscopy, optic microscopy, transmission electronic microscopy and gel electrophoresis. After subsequent addition of salt to the nanoparticles solution, secondary aggregation increased the size of the polyplexes. The nanoparticles stability decreased drastically at the ionic strengths 150 and 500mM, which caused the corresponding decrease in the thickness of the stabilising shell. The morphologies of chitosan/DNA nanoparticles at those ionic strengths were a mixture of large spherical aggregates, toroids and rods. The results indicated that to obtain stable chitosanDNA nanoparticles, besides molecular weight and N/P ratio, it is quite important to control the ionic strength of the solution. (AU)