Related Experiment Video
Updated: May 21, 2026
10:15
Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Role of lipid ordered/disordered phase coexistence in pulmonary surfactant function
Cristina Casals1, Olga Cañadas
1Departamento de Bioquimica y Biologia Molecular, Universidad Complutense de Madrid, Madrid, Spain. ccasalscc@bio.ucm.es
Biochimica Et Biophysica Acta
|June 5, 2012
Summary
Lung surfactant membranes feature coexisting lipid phases, crucial for breathing. This phase coexistence aids in forming 3D structures, stabilizing lungs during breathing cycles.
Area of Science:
- Pulmonary physiology
- Biophysics
- Biochemistry
Background:
- The respiratory epithelium generates complex extracellular membranes vital for respiration.
- Pulmonary surfactant, forming a monolayer at the air-liquid interface, reduces surface tension, preventing lung collapse and aiding inflation.
Purpose of the Study:
- To review the ordered/disordered lipid phase coexistence in lung surfactant.
- To explore the role of domain boundaries in the monolayer-to-multilayer transition.
- To correlate biophysical inactivation of pulmonary surfactant with alterations in phase coexistence.
Main Methods:
- Literature review of studies on lung surfactant structure and function.
- Analysis of biophysical properties related to lipid phase behavior.
- Examination of the relationship between phase coexistence and surfactant inactivation.
Main Results:
- Lung surfactant membranes exhibit two distinct micrometer-sized ordered/disordered lipid phases at physiological temperatures.
- Phase coexistence may facilitate the formation of 3D structures during exhalation, enabling minimal surface tension.
- These structures may serve as a reserve, mitigating tension increases during inhalation.
Conclusions:
- Ordered/disordered lipid phase coexistence is a key feature of lung surfactant.
- Domain boundaries likely play a role in the transition from monolayer to multilayer structures.
- Alterations in phase coexistence are linked to the biophysical inactivation of pulmonary surfactant.
Related Concept Videos
01:30Micelles
Micelle formation is an intricate process that hinges on the properties of amphiphilic or amphipathic molecules and the conditions of the system in which they are found. Amphiphilic molecules, which have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts, play a critical role in this process.In aqueous environments, these molecules arrange themselves such that their hydrophilic heads are turned towards the water phase, while their hydrophobic tails are oriented away...
01:27Surface Active Agents
Surfactants, named for their behavior at interfaces, positively adsorb at the interfaces of two phases, reducing interfacial tension. Their versatility as emulsifiers, detergents, and foaming agents stems from this ability. Surfactants, often termed amphiphiles, share the property of amphipathy, with molecules having both hydrophilic and hydrophobic portions. The hydrophilic part is called the head, and the hydrophobic part, including an elongated alkyl substituent, forms the tail.Surfactants...
01:35Asymmetric Lipid Bilayer
Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. The treatment of the erythrocyte membrane with the enzyme phospholipase confirmed the asymmetric nature of the lipid bilayer. The enzyme hydrolyzes lipids into fatty acids and hydrophilic groups. The phospholipase acts only on the outer layer of the membrane, while the inner layer remains intact. The phospholipase treatment resulted in 80%...
01:26Membrane Fluidity
Membrane fluidity is explained by the fluid mosaic model of the cell membrane, which describes the plasma membrane structure as a mosaic of components—including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character.
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is a relatively...
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is a relatively...
01:23Membrane Fluidity
Cell membranes are composed of phospholipids, proteins, and carbohydrates loosely attached to one another through chemical interactions. Molecules are generally able to move about in the plane of the membrane, giving the membrane its flexible nature called fluidity. Two other features of the membrane contribute to membrane fluidity: the chemical structure of the phospholipids and the presence of cholesterol in the membrane.
01:31What are Lipids?
Lipids function as structural components of cellular membranes, in addition to acting as energy reservoirs and signaling molecules. They are thus crucial to all living organisms. The three biologically important classes of lipids are triglycerides, phospholipids, and steroids.
Non-Polar and Hydrophobic Characteristics of Lipids
Lipids are a structurally and functionally diverse group of hydrocarbons—compounds consisting of carbon and hydrogen atoms. The carbon-carbon and carbon-hydrogen bonds...
Non-Polar and Hydrophobic Characteristics of Lipids
Lipids are a structurally and functionally diverse group of hydrocarbons—compounds consisting of carbon and hydrogen atoms. The carbon-carbon and carbon-hydrogen bonds...