Cationic lipids and polymers are widely used as transfection reagents in molecular biology, allowing for the introduction of exogenous nucleic acids into cells. These reagents form complexes with negatively charged genetic material, such as plasmid DNA or siRNA, which can then enter cells and release the genetic material for integration or transient expression. Cationic lipids and polymers offer several advantages over other methods of gene delivery, including ease of use, cost-effectiveness, and low immunogenicity.

They are also applicable to a wide range of cell types, including primary and difficult-to-transfect cells. However, their low transfection efficiency and limited cargo capacity remain significant challenges, prompting ongoing research into improving their performance.