Cationic lipids are conceptually and methodologically simple tools to deliver nucleic acids into the cells. Strategies based on cationic lipids are viable alternatives to viral vectors and are becoming increasingly popular owing to their minimal toxicity. The first-generation cationic lipids were built around the quaternary nitrogen primarily for binding and condensing DNA. A large number of lipids with variations in the hydrophobic and hydrophilic region were generated with excellent transfection efficiencies in vitro. These cationic lipids had reduced efficiencies when tested for gene delivery in vivo. Efforts in the last decade delineated the cell biological basis of the cationic lipid gene delivery to a significant detail. The application of techniques such as small angle X-ray spectroscopy (SAXS) and fluorescence microscopy, helped in linking the physical properties of lipid:DNA complex (lipoplex) with its intracellular fate. This biological knowledge has been incorporated in the design of the second-generation cationic lipids. Lipid-peptide conjugates (peptoids) are effective strategies to overcome the various cellular barriers along with the lipoplex formulations methodologies. In this context, cationic lipid-mediated gene delivery is considerably benefited by the methodologies of liposome-mediated drug delivery. Lipid mediated gene delivery has an intrinsic advantage of being a biomimetic platform on which considerable variations could be built to develop efficient in vivo gene delivery protocols.
Recombinant proteins that are heterologous fusions, having DNA-binding domains and nuclear localization epitopes, generated in this study have considerable potential to facilitate DNA delivery and enhance transfection. The domains in these fusion proteins would be promising in the development of non-viral gene delivery vectors particularly in cells that do not divide.
A novel series of cationic amphiphiles based on dialkyl glutamides with cationic pyridinium head group were synthesized as potential gene delivery agents. Four cationic lipids with glutamide as linker and varying chain lengths were tested for their transfection efficiency in three cell lines. The DNA-lipid complexes were characterized for their ability to bind to DNA, protection from nuclease digestion, size, zeta-potential, and toxicity. All four lipids demonstrated efficient transfection in MCF-7, COS, and HeLa cells, and the reporter gene expression was much higher with DOPE as the helper lipid in the formulation when compared to cholesterol. Among these 14-carbon lipids, lipid 2 has shown the highest transfection efficiency, complete protection of DNA from nuclease digestion, and low toxicity. Interestingly, lipid 2 has also shown remarkable enhancement in transfection in the presence of serum.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.