Mikrofibril

Mikrofibril, or microfibril, denotes a slender, elongated fibrillar structure on the nanometer scale that serves as a fundamental building block in many tissues. Depending on context, microfibrils range in diameter roughly from 5 to 25 nanometers and can form higher-order fibers or networks that give tissues and cells mechanical strength and shape.

In plants, cellulose microfibrils are crystalline assemblies of cellulose chains produced at the plasma membrane by cellulose synthase complexes. Their orientation, guided by underlying microtubule tracks, directs cell expansion and tissue architecture, while cross-linking to matrix polysaccharides helps determine wall rigidity.

In animals, fibrillin-containing microfibrils are extracellular matrix components that assemble into microfibril bundles around elastin to form elastic fibers. They act as structural scaffolds and regulate growth factor signaling. Defects in fibrillin-1 can cause Marfan syndrome and related disorders.

In other contexts, microfibrils can refer to thin cytoskeletal or extracellular filaments observed in different tissues, and the term is also used in botany and materials science to describe nanofiber reinforcements in composites.