Liposome

A liposome is a spherical vesicle having at least one lipid bilayer. Liposomes can be composed of naturally-derived phospholipids with mixed lipid chains (like egg phosphatidylethanolamine), or of pure surfactant components like DOPE (dioleoylphosphatidylethanolamine). They are typically created to carry hydrophobic or hydrophilic molecules. Hydrophobic molecules can insert themselves into the lipid bilayer, and hydrophilic molecules can be entrapped in the aqueous interior.

Liposomes can range in size from very small (around 25 nanometers) to large (several micrometers). They are used in a variety of applications, including drug delivery, gene therapy, and cosmetics. The biocompatibility and biodegradability of liposomes make them attractive vehicles for delivering therapeutic agents. The lipid bilayer structure allows for the encapsulation and protection of sensitive drugs or genetic material from degradation or clearance by the body before reaching the target site.

The formation of liposomes is typically achieved through methods such as sonication, extrusion, or film hydration, followed by techniques to control size and lamellarity (number of bilayers). Different lipid compositions and preparation methods can result in liposomes with varying characteristics, such as size, charge, stability, and drug release properties. These characteristics are crucial for tailoring liposomes to specific applications.

Liposomes can be further modified with targeting ligands, such as antibodies or peptides, to enhance their specificity for certain cells or tissues. This targeted delivery can improve the efficacy of therapeutic agents and reduce side effects.

The study of liposomes and their applications is an active area of research, with ongoing efforts to improve their stability, targeting capabilities, and drug loading capacity. They are a versatile tool in biomedicine and nanotechnology.