Gemini surfactant dimethylene-1,2-bis(tetradecyldimethylammonium bromide)-based gene vectors: A biophysical approach to transfection efficiency

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.

Comparison of the Efficiency of Complexes Based on S413-PV Cell-Penetrating Peptides in Plasmid DNA and siRNA Delivery

“…In this regard, complex physicochemical properties, such as size and surface charge, could be on the basis of different cellular uptake yields through the preferential use of distinct internalization pathways. However, in contrast with previous observations, 11,44 physicochemical characterization of the binary and ternary systems revealed no significant differences in terms of size or charge density between complexes with different transfection efficiencies in HeLa cells. In fact, S4-13 PV/pDNA complexes at the 5/1 (+/−) charge ratio (1412.0 nm and +9.6 mV) mediated efficient transfection as opposed to H 5 -S4- 13 PV/ pDNA complexes at the same charge ratio, which showed similar size and zeta potential (1108.5 nm and +9.6 mV).…”

New cationic nanovesicular systems containing lysine-based surfactants for topical administration: Toxicity assessment using representative skin cell lines

“…Cationic lipid-based nanovesicles have been proposed as biocompatible drug delivery devices, with specific properties and able to overcome the barriers imposed by cell membranes [1]. Among various cationic substances, cationic amphiphile molecules have been successfully used in the composition of such carriers [1,2].…”

“…Among various cationic substances, cationic amphiphile molecules have been successfully used in the composition of such carriers [1,2]. Lipid-based devices have a broad spectrum of applications, one of which is the topical delivery of active ingredients, intensively studied in recent years [3,4].…”

Arginine-based cationic liposomes for efficient in vitro plasmid DNA delivery with low cytotoxicity

“…39 The physicochemical properties (ie, size and zeta potential) of lipoplexes strongly influence their gene delivery efficiency. [40][41][42] It has been reported that lipoplexes with larger particle size show elevated transfection efficiency because of their maximum contact with the cells, and larger particles taken up by cells lead to the formation of large intracellular vesicles that are more easily disrupted, thus releasing DNA into the cytoplasm. 43 Our data also indicate that larger lipoplex particles formed when prepared in the absence of serum than when in the presence of serum and thus elevated transfection efficiency in the absence of serum.…”