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Among polymeric polycations, chitosan has emerged as a powerful carrier for gene delivery. Only a few studies have focused on the stability of the chitosan/DNA complex under storage, although this is imperative for nanomedicinal applications. Here, we synthesized polyelectrolyte complexes at a charge ratio of 10 using 50 kDa chitosan and plasmid (p)DNA that encodes a GFP reporter. These preparations were stable up to 3 months at 4 A degrees C and showed reproducible transfection efficiencies in vitro in HEK293 cells. In addition, we developed a methodology that increases the in vitro transfection efficiency of chitosan/pDNA complexes by 150 % with respect to standard procedures. Notably, intracellular pDNA release and transfected cells peaked 5 days following transection of mitotically active cells. These new developments in formulation technology enhance the potential for polymeric nanoparticle-mediated gene therapy.

Among polymeric polycations, chitosan has emerged as a powerful carrier for gene delivery. Only a few studies have focused on the stability of the chitosan/DNA complex under storage, although this is imperative for nanomedicinal applications. Here, we synthesized polyelectrolyte complexes at a charge ratio of 10 using 50 kDa chitosan and plasmid (p)DNA that encodes a GFP reporter. These preparations were stable up to 3 months at 4 A degrees C and showed reproducible transfection efficiencies in vitro in HEK293 cells. In addition, we developed a methodology that increases the in vitro transfection efficiency of chitosan/pDNA complexes by 150 % with respect to standard procedures. Notably, intracellular pDNA release and transfected cells peaked 5 days following transection of mitotically active cells. These new developments in formulation technology enhance the potential for polymeric nanoparticle-mediated gene therapy.

In the last few decades, there has been a growing interest towards the use of delivery systems for a more effective treatment of various diseases and the research increasingly focused on designing innovative solutions based on intra-cellular vectors. Among them, biocompatible DNA-polyelectrolyte complexes appear as a promising strategy for in vivo delivery of biologically active macromolecules. One of the most largely employed cationic polymer is Chitosan, which is special for its biological properties such as biodegradability, biocompatibility, mucoadhesivity, and permeability enhancer capacity. Due to this, complexes formed by condensation of DNA by Chitosan have been largely investigated for their potential use in gene therapy. Nevertheless the extensive efforts, the correlation between the physicochemical properties of the Chitosan-DNA polyplexes with their transfection efficiency still remains a central challenge. Moreover, the criteria and strategies for the design of efficient Chitosan-based gene delivery systems remain inconclusive. In a recent paper, we studied the aggregation behavior of Chitosan-DNA complexes and compared it with the predictions of existing models for the complexation of oppositely charged polyelectrolytes, showing that these models can serve as useful guide for the optimization of the complexes. Here, in order to understand the relation between physicochemical and transfection properties of Chitosan-DNA complexes, we study the efficiency of Chitosan-pDNA aggregates obtained indifferent conditions as vectors for DNA transfection. Small, globular and positively charged aggregates formed at large Chitosan excess, which can be obtained independently of the length of the Chitosan employed, appear to be the more effective for transfection, the more stable aggregates resulting the ones formed with longer chains. (C) 2013 Elsevier B.V. All rights reserved.

In the last few decades, there has been a growing interest towards the use of delivery systems for a more effective treatment of various diseases and the research increasingly focused on designing innovative solutions based on intra-cellular vectors. Among them, biocompatible DNA-polyelectrolyte complexes appear as a promising strategy for in vivo delivery of biologically active macromolecules. One of the most largely employed cationic polymer is Chitosan, which is special for its biological properties such as biodegradability, biocompatibility, mucoadhesivity, and permeability enhancer capacity. Due to this, complexes formed by condensation of DNA by Chitosan have been largely investigated for their potential use in gene therapy. Nevertheless the extensive efforts, the correlation between the physicochemical properties of the Chitosan-DNA polyplexes with their transfection efficiency still remains a central challenge. Moreover, the criteria and strategies for the design of efficient Chitosan-based gene delivery systems remain inconclusive. In a recent paper, we studied the aggregation behavior of Chitosan-DNA complexes and compared it with the predictions of existing models for the complexation of oppositely charged polyelectrolytes, showing that these models can serve as useful guide for the optimization of the complexes. Here, in order to understand the relation between physicochemical and transfection properties of Chitosan-DNA complexes, we study the efficiency of Chitosan-pDNA aggregates obtained indifferent conditions as vectors for DNA transfection. Small, globular and positively charged aggregates formed at large Chitosan excess, which can be obtained independently of the length of the Chitosan employed, appear to be the more effective for transfection, the more stable aggregates resulting the ones formed with longer chains. (C) 2013 Elsevier B.V. All rights reserved.

In the last few decades, there has been a growing interest towards the use of delivery systems for a more effective treatment of various diseases and the research increasingly focused on designing innovative solutions based on intra-cellular vectors. Among them, biocompatible DNA-polyelectrolyte complexes appear as a promising strategy for in vivo delivery of biologically active macromolecules. One of the most largely employed cationic polymer is Chitosan, which is special for its biological properties such as biodegradability, biocompatibility, mucoadhesivity, and permeability enhancer capacity. Due to this, complexes formed by condensation of DNA by Chitosan have been largely investigated for their potential use in gene therapy. Nevertheless the extensive efforts, the correlation between the physicochemical properties of the Chitosan-DNA polyplexes with their transfection efficiency still remains a central challenge. Moreover, the criteria and strategies for the design of efficient Chitosan-based gene delivery systems remain inconclusive. In a recent paper, we studied the aggregation behavior of Chitosan-DNA complexes and compared it with the predictions of existing models for the complexation of oppositely charged polyelectrolytes, showing that these models can serve as useful guide for the optimization of the complexes. Here, in order to understand the relation between physicochemical and transfection properties of Chitosan-DNA complexes, we study the efficiency of Chitosan-pDNA aggregates obtained indifferent conditions as vectors for DNA transfection. Small, globular and positively charged aggregates formed at large Chitosan excess, which can be obtained independently of the length of the Chitosan employed, appear to be the more effective for transfection, the more stable aggregates resulting the ones formed with longer chains. (C) 2013 Elsevier B.V. All rights reserved.