Bulk and Microfluidic Synthesis of Stealth and Cationic Liposomes for Gene Delivery Applications

This chapter describes the synthesis of stealth and cationic liposomes and their complexation with plasmid DNA to generate lipoplexes for gene delivery applications. Two techniques are presented: a top-down approach which requires a second step of processing for downsizing the liposomes (i.e., ethanol injection method) and a microfluidic technique that explores the diffusion of ethanol in water to allow the proper lipid self-assembly. The synthesis of stealth liposomes is also a challenge since the use of poly(ethylene glycol) favors the formation of oblate micelles. In this protocol, the stealth cationic liposome synthesis by exploring the high ionic strength to overcome the formation of secondary structures like micelles is described. Finally, the electrostatic complexation between cationic liposomes and DNA is described, indicating important aspects that guarantee the formation of uniform lipoplexes.