There are several methods to prepare unilamellar liposomes and the protocols differ based on the type of desired unilamellar vesicles. Different lipids can be bought either dissolved in chloroform or as lyophilized lipids. In the case of lyophilized lipids, they can be solubilized in chloroform. Lipids are then mixed with a desired molar ratio. Then chloroform is evaporated using a gentle stream of nitrogen (to avoid oxygen contact and oxidation of lipids) at room temperature. A rotary evaporator can be used to form a homogeneous layer of liposomes. This step removes the bulk of chloroform. To remove the residues of trapped chloroform, lipids are placed under vacuum from several hours to overnight. Next step is re-hydration where the dried lipids are re-suspended in the desired buffer. Lipids can be vortexed for several minutes to insure that all the lipid residues get re-suspended. SUVs can be obtained in via two methods. Either by sonication (for instance with 1 second pulses in 3 Hz cycles at a power of 150 W) or by extrusion. In extrusion method, the lipid mixture is passed through a membrane for 10  or more times. Depending on the size of the membrane, either SUVs or LUVs can be obtained. Keeping vesicles under argon and away from oxygen and light can extend their lifetime.