Vesicle (biology and chemistry)

Liposome scheme-en

Vesicle in biology and chemistry refers to a small structure within a cell, or a small, enclosed compartment that is separated from the cytosol by at least one lipid bilayer. Vesicles play key roles in transporting materials within and outside the cell, in processes such as endocytosis, exocytosis, and transcytosis. They are also involved in metabolism, enzyme storage, and the detoxification of harmful substances.

Biology

In the biological context, vesicles are critical components of the cellular machinery. They are involved in the transport of molecules between different compartments within the cell, as well as the exchange of substances between the cell and its external environment. There are several types of vesicles, each with specific functions:

• Lysosomes - contain digestive enzymes that break down macromolecules, old cell parts, and microorganisms.
• Endosomes - involved in the sorting, modification, and directing of vesicle contents.
• Secretory vesicles - store and transport proteins and lipids to be secreted from the cell.
• Transport vesicles - shuttle lipids and proteins between various compartments within the cell, such as the endoplasmic reticulum, Golgi apparatus, and plasma membrane.
• Autophagosomes - involved in autophagy, they help in degrading and recycling cellular components.

Chemistry

In chemistry, vesicles can refer to small, spherical compartments, encapsulated by a lipid bilayer, that can be formed artificially. These structures are similar to the vesicles found in biological systems and can be used to study the properties of biological membranes, the encapsulation and delivery of drugs, and the principles of self-assembly and molecular organization. Chemically synthesized vesicles are often used in the field of nanotechnology and material science for the development of drug delivery systems, artificial cells, and biosensors.

Formation

Vesicles can form naturally within the cell through processes such as budding from the Golgi apparatus or the endoplasmic reticulum. In chemistry, vesicles can be formed through methods such as hydration of dried phospholipids, which leads to the self-assembly of lipid molecules into bilayers, encapsulating a portion of the solvent inside.

Function

The primary function of vesicles in biology is to transport materials. In the cell, vesicles can help isolate potentially harmful substances, transport enzymes and nutrients, and facilitate communication between cells through the release of neurotransmitters and hormones. In chemistry, synthetic vesicles can be designed to deliver drugs to specific sites within the body, thereby improving the efficacy and reducing the side effects of treatments.

See also

• Cell (biology)
• Membrane biology
• Liposome
• Phospholipid