| Abstract: | Certain disease states can be corrected by using nucleic acids as therapeutic agents. To achieve this, nucleic acids must be delivered into the affected cells efficiently. At the core of a successful gene therapy protocol is the design of the nucleic acid carrier. Cationic lipids, as one of the gene delivery systems, have a wide potential in delivering nucleic acids both in vivo and in vitro. They are synthetic in origin and, hence, can be produced in required quantities and are biologically safe. Significant inputs from synthetic chemists in the recent past have resulted in the exploration of cationic lipids with very interesting functionalities. Transfection efficiencies of cationic lipids are comparable to viral-mediated transfection in vitro. However, viral-based methods for gene delivery in vivo are comparatively more efficient. Current understanding of lipid-mediated transfection is partially due to incomplete characterisation of the lipoplex, poor understanding of cell biology of transfection and cell type variations in transfection efficiencies. The published patents and research demonstrates the need for incorporation of the biological information in the design of the gene delivery formulations. In this review, the cell biological aspects critical for lipid-mediated transfection are emphasised. The parameters that influence the colloidal stability of the lipoplexes, cell biological processes relevant to gene delivery, such as cell association/uptake, cytoplasmic stability of the DNA and nuclear import, are discussed. The main focus of this review is patents published in the last 5 years. |
