Please use this identifier to cite or link to this item: https://hdl.handle.net/10216/100949
Author(s): Ana M S Cardoso
Henrique Faneca
Joao A S Almeida
Alberto A C C Pais
Eduardo F Marques
Maria C P Pedroso de Lima
Amalia S Jurado
Title: Gemini surfactant dimethylene-1,2-bis(tetradecyldimethylammonium bromide)-based gene vectors: A biophysical approach to transfection efficiency
Issue Date: 2011
Abstract: Cationic liposomes have been proposed as biocompatible gene delivery vectors, able to overcome the barriers imposed by cell membranes. Besides lipids, other surfactant molecules have been successfully used in the composition of gene carriers. In the present work, we used a Gemini surfactant, represented by the general structure [C(14)H(29)(CH(3))(2)N(+)(CH(2))(2)N(+)(CH(3))(2)C(14)H(29)]2Br(-) and herein designated 14-2-14, to prepare cationic gene carriers, both as the sole component and in combination with neutral helper lipids, cholesterol and DOPE. The effectiveness of three Gemini-based formulations, namely neat 14-2-14, 14-2-14:Chol (1:1 molar ratio) and 14-2-14:Chol:DOPE (2:1:1 molar ratio), to mediate gene delivery was evaluated in DNA mixtures of +/- charge ratios ranging from 1/1 to 12/1. After ruling out cytotoxicity as responsible for the differences observed in the transfection competence, structural and physical properties of the vector were investigated, using several techniques. The size and surface charge density (zeta potential) of surfactant-based structures were determined by conventional techniques and the thermotropic behaviour of aqueous dispersions of surfactant/lipid/DNA formulations was monitored by fluorescence polarization of DPH and DPH-PA probes. The capacity of lipoplexes to interact with membrane-mimicking lipid bilayers was evaluated, using the PicoGreen assay and a FRET technique. Our data indicate inefficiency of the neat 14-2-14 formulation for gene delivery, which could result from the large dimensions of the particles and/or from its relative incompetence to release DNA upon interaction with anionic lipids. The addition of cholesterol or cholesterol and DOPE conferred to Gemini-based gene carrier transfection activity at specific ranges of +/- charge ratios. Fluorescence polarization data suggest that an order parameter within a specific range was apparently needed for complexes to display maximal transfection efficiency. The transfection-competent formulations showed to be efficiently destabilized by interaction with different anionic and zwitterionic bilayers, including those containing PS and cardiolipin. These data are discussed in terms of the potential of these formulations to address different intracellular targets.
Subject: Espectroquímica, Química das superfícies, Química aplicada, Ciências biológicas
Spectrochemistry, Surface chemistry, Applied chemistry, Biological sciences
Scientific areas: Ciências exactas e naturais::Ciências biológicas
Natural sciences::Biological sciences
URI: https://repositorio-aberto.up.pt/handle/10216/100949
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FCUP - Artigo em Revista Científica Internacional

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