bilayer (rus. бислой otherwise липидный бислой) — double molecular layer formed from polar lipids in aqueous solution.


In a lipid bilayer, molecules are oriented in such a way that their polar fragments are turned towards the aqueous phase and form two hydrophilic surfaces, and non-polar tails form a hydrophobic region within the bilayer (see Fig.). A bilayer is a thermodynamically favourable structure of polar lipids in aqueous solution. Virtually all biological membranes are made mostly of phospholipid (phosphatidylcholine, phosphatidylserine, etc.) bilayers. A bilayer is usually 4-5 nm thick. Phospholipids are used to produce liposomes and nanosomes for the encapsulation and delivery of biologically active substances in medicine and cosmetology.


Lipid bilayer structure: the polar
Lipid bilayer structure: the polar "head" of molecule is marked red, and the non-polar "tail" (hydrocarbon chain) is marked grey.


  • Eremin Vadim V.
  • Shirinsky Vladimir P.


  1. Chemical encyclopedia (in Russian). V. 2. — Moscow: Sovetskaja ehnciklopedija, 1990. — 597 p.

Contact us