Semipermeable membrane

A **semipermeable membrane** is a barrier—biological (as with cell membranes) or synthetic—that selectively allows certain molecules or ions to pass through while restricting others, based on factors like size, charge, and solubility[1][2][3][5][7][8]. In cells, the semipermeable property arises principally from the **phospholipid bilayer and embedded proteins**, which facilitate the regulated transport of water, nutrients, and signaling molecules. This selective permeability is essential for maintaining homeostasis, osmoregulation, and cellular integrity[2][3][5][6][7]. In medicine and engineering, semipermeable membranes are integral to applications such as dialysis, water purification (reverse osmosis), and selective barrier devices[4]. While membrane proteins within semipermeable membranes are frequent drug targets, the membrane as a whole is not considered a therapeutic target. If a therapeutic target is sought, further specification (e.g., "aquaporin channel," "Na+/K+ transporter," "G protein-coupled receptor") is required.

Other names

Selectively permeable membraneDifferentially permeable membraneBiological barrier (sometimes used, but non-specific)