Lipid nanoparticles of internal cubic symmetry, termed cuboplexes, are potential nonviral delivery vehicles for gene therapy due to their "topologically active" nature, which may enhance endosomal escape and improve delivery outcomes. In this study, we have used cationic cuboplexes, based on monoolein (MO) doped with a cationic lipid, for the encapsulation and delivery of antisense green fluorescent protein (GFP)-small interfering RNA (siRNA) into Chinese Hamster Ovary (CHO)-GFP cells. Agarose gel electrophoresis has confirmed the successful encapsulation of siRNA within cationic cubosomes, while synchrotron small-angle X-ray scattering (SAXS) demonstrated that the underlying cubic nanostructure of the particles was retained following encapsulation. The cationic cubosomes were shown to be reasonably nontoxic against the CHO-GFP cell line. Fluorescence-activated cell sorting (FACS) provided evidence of the successful transfection to CHO-GFP cells. Knockdown efficiency was strongly linked to the type of cationic lipid used, although all cubosomes had essentially the same internal nanostructure. The gene knockdown efficiency for some cationic cubosomes was shown to be higher than lipofectamine, which is a commercially available liposome-based formulation, while the controlled release of the siRNA from the cubosomes over a 72 h period was observed using confocal microscopy. This combination exemplifies the potential of cationic cuboplexes as a novel, nonviral, controlled-release delivery vector for siRNA.
Keywords: SAXS; antisense GFP-siRNA; cuboplex; cubosome; high-throughput; lyotropic liquid crystals; monoolein; nanoparticles; self-assembly.