Adhäsions

Adhäsions, or adhesion, is the tendency of different substances or surfaces to cling to one another. In materials science, adhesion results from a mix of intermolecular forces such as van der Waals forces, electrostatic interactions, hydrogen bonding, and, when relevant, chemical bonds. The strength and character of adhesion depend on surface chemistry, roughness, cleanliness, and the surrounding environment, including liquids. In scientific terms, adhesion describes the attraction between unlike materials, while cohesion refers to the attraction within a single material.

In biology, adhesion covers how cells attach to each other and to the extracellular matrix. This process is mediated by cell adhesion molecules (CAMs) such as cadherins, integrins, selectins, and immunoglobulin superfamily proteins. Cell-cell adhesion helps maintain tissue structure, whereas cell-matrix adhesion links cells to the extracellular matrix and transduces signals that regulate movement, growth, and survival. Microorganisms also rely on adhesion to colonize surfaces; bacteria use adhesins, pili, and fimbriae to attach to host tissues and to form biofilms.

Medically, adhesions refer to fibrous bands that form between tissues or organs after surgery, infection, or inflammation. In the abdomen or pelvis, such adhesions can cause pain, restricted movement, infertility, or intestinal obstruction. Prevention focuses on careful surgical technique, minimizing tissue trauma, and using barrier methods or anti-adhesion fluids. When adhesions cause problems, treatment may involve adhesiolysis, the surgical separation of the bands. Ongoing research in adhesion science seeks better biomaterials, barriers, and pharmacological approaches to reduce postoperative adhesion formation.