liposomeforming

Liposomeforming refers to the set of laboratory methods used to assemble lipid bilayer vesicles, or liposomes, from amphiphilic lipid molecules in an aqueous medium. Liposomes are typically composed of phospholipids, often with cholesterol and sometimes surface modifiers such as polyethylene glycol, and they range from tens to hundreds of nanometers in diameter. The driving principle is the hydrophobic effect: amphiphiles arrange into bilayers that shield hydrophobic tails from water, trapping an aqueous interior within a closed vesicle. The resulting size and lamellarity (multilamellar versus unilamellar) are strongly influenced by preparation method and conditions such as lipid concentration, temperature, and ionic strength.

Common liposomeforming methods include:

- Thin-film hydration, where a dried lipid film is hydrated to form multilamellar vesicles, typically followed by sonication or extrusion to produce smaller, unilamellar liposomes.

- Extrusion through polycarbonate membranes to narrow size distribution.

- Ethanol injection or solvent evaporation, in which lipids dissolved in an organic solvent are rapidly mixed with aqueous buffer to yield small vesicles.

- Microfluidic or rapid-mixing approaches that enable tighter control of size and lamellarity.

- Detergent-mediated reconstitution and detergent removal, used to assemble liposomes or reconstitute membrane proteins.

- Reverse-phase evaporation, which can generate large unilamellar vesicles.

Characterization often includes size distribution by dynamic light scattering, zeta potential, and encapsulation efficiency. Applications span drug and gene delivery, vaccine formulations, and cosmetics. Limitations include stability and storage challenges, potential leakage of encapsulated contents, and scalability issues for some methods. Liposomeforming remains a rapidly evolving area, with ongoing work to improve uniformity, loading efficiency, and in vivo performance.