Enhanced Transfection Rates of Small-Interfering RNA Using Dioleylglutamide-Based Magnetic Lipoplexes

Abstract

Magnetic force-guided delivery (magnetofection) has been studied as a new modality for introducing small-interfering RNA (siRNA) into target cells, but its delivery efficiency needs to be improved. Here, we report that magnetofection of N,N''-dioleylglutamide (DG)-based magnetic lipoplexes can substantially enhance the cellular delivery rates of siRNA. The siRNA was triply complexed with DG-based cationic liposomes and cationic iron-oxide nanoparticles. The formation of siRNA-containing magnetic lipoplexes was confirmed by gel retardation, sizes, and zeta potential values. Fluorescence microscopy and flow cytometry of fluorescent marker-labeled siRNA revealed that the DG-based magnetic lipoplexes conferred a higher cellular delivery rate of siRNA than DG-based lipoplexes or Lipofectamine 2000. In addition to the enhanced delivery of siRNA, the DG-based magnetic lipoplexes showed lack of cytotoxicity. We then tested the application of these magnetic lipoplexes for the cellular delivery of anticancer siRNA. Cancer cell lines magnetofected with DG-based magnetic lipoplexes containing Mcl1-specific siRNA (siMcl1) showed much lower viability than the groups treated with DG-based lipoplexes or Lipofectamine 2000, indicating that our magnetofection strategy conferred greater siMcl1-induced anticancer activity. These results suggest that DG-based magnetic lipoplexes are promising candidates for enhancing the efficiency of magnetic field-guided siRNA delivery.

Delivery of Short Interfering Ribonucleic Acid-Complexed Magnetic Nanoparticles in an Oscillating Field Occurs via Caveolae-Mediated Endocytosis

“…We observed a physiological knock-down of actin in HeLa cells, in a dose-dependent manner, as observed using the adhesion assay. Others have successfully knocked-down various genes in HeLa cells or other cell lines using a combination of cationic liposomes and/or magnetofection with a stationary magnet [28], [29], [30]. While transfection efficiencies of siRNA between lipid methodology and magnetofection were similar, the significant difference is one of viability – with lipid methodology causing greater cell death compared to magnetofection [31].…”

Cross‐linked Iron Oxide Nanoparticles for Therapeutic Engineering and in Vivo Monitoring of Mesenchymal Stem Cells in Cerebral Ischemia Model

“…In addition, magnet‐labeled cells, obtained by internalization of IONs, could allow magnet‐derived retention and accumulation at target sites which could boost therapeutic effects. To elevate efficiency of magnet‐derived gene transfer for genetic engineering of therapeutic cells, design and application for novel iron oxide based carriers including micelles, liposomes, and nanoparticles have been intensively studied …”

Superparamagnetic iron oxide nanoparticle-based delivery systems for biotherapeutics

“…Magnetic nanoparticles coated with hydrophilic polymers can be loaded within the core of liposomes or attached to the surface of liposomes via ionic interactions. Commercial cationic iron oxide nanoparticles (CombiMAG, Chemicell GmbH) has been complexed with N,N″-dioleylglutamide (DG)-based lipoplexes/siRNA via electrostatic interactions for magnetically-driven delivery of therapeutic siRNA against Mcl1 gene [68]. By measuring the amounts of transfected cells with fluorescence-labeled siRNAs using flow cytometry, the investigators demonstrated that the exposure of CombiMAG/lipoplexes/siRNA complexes to a magnetic field for 15 min significantly increased the efficiency of intracellularly delivered siRNA by 2–5-fold in various types of cancer cells studied, including human lung cancer, breast cancer, and cervical cancer cells.…”

“…Polyarginine, polylysine, and PEI were conjugated to PEG immobilized SPIONs to attach siRNAs via ionic interactions and escape from endosome [93]. The cationic liposomes composed of N,N-dioleylglutamide were complexed with siRNAs to form lipoplexes, which subsequently mixed with cationic iron oxide nanoparticles (CombiMAG) [68]. In the presence of an external magnetic field, intracellular uptake of lipoplexes/iron oxide nanoparticles mostly occurs within 30 min, while intracellular delivery by conventional lipoplexes takes more than 3 hrs in vitro .…”

“…To enhance transfection efficiency, the commercialized magnetic nanoparticle CombiMag (OZ Biosciences) has been used as an additive for gene transfection [22, 68, 95]. After mixing transfection reagents with therapeutic gene, CombiMag is added to the mixture, which resulted in 3-fold higher gene transfection in A549 cells (human lung carcinoma cells) than conventional liposomal transfection using lipofectamine [95].…”