ABSTRACT
The mature small interfering RNA (siRNA) shares partial complementary sequences in the 3' UTR of a target mRNA. Cationic lipids and polymers are two major classes of nonviral delivery carriers that can form complexes with negatively charged siRNA. Nanoparticles are appropriate delivery systems that facilitate siRNA transport in the cytosol through electrostatic interactions with negatively charged phospholipid bilayers or through specific targeting moieties. Encapsulation of siRNA in liposomes and other nanoparticles is one of the preferred approaches. Numerous cationic lipids generated by combinatorial synthesis have been screened for optimal siRNA delivery. Lipidoids are lipid-like molecules, synthesized by a one-step synthetic scheme. The nature and extent of these gene expression changes are dependent on several factors, including delivery system variables such as its chemistry, lipid architecture, charge, and dose; the degree of saturation, nature of cationic lipids, fusogenicity, cellular uptake, gene silencing ability, and biological variables.
