Pulmonary surfactant lipid monolayer (PS)

The pulmonary surfactant lipid monolayer is a complex mixture of lipids, primarily dipalmitoylphosphatidylcholine (DPPC), and specific surfactant proteins (SP-A, SP-B, SP-C, and SP-D) that lines the alveolar surface at the air-liquid interface (StatPearls: NBK541005). Its primary biological function is to reduce surface tension within the lungs, which prevents alveolar collapse (atelectasis) during expiration and increases pulmonary compliance (NIH: PMC3101431). In clinical conditions such as Infant Respiratory Distress Syndrome (IRDS), a deficiency in this monolayer leads to severe respiratory failure and high mortality if untreated (PubMed: 11115269). Therapeutic intervention involves the administration of exogenous surfactants—either animal-derived or synthetic—which integrate into the interface to restore lung mechanics (NIH: PMC3101431). Beyond mechanical stabilization, the surfactant system plays a crucial role in the innate immune response by facilitating the clearance of pathogens through opsonization (StatPearls: NBK541005). Modern drug development focuses on synthetic peptide-based surfactants to overcome the limitations and potential immunogenicity of animal-derived products (PubMed: 11115269).

Other names

Alveolar surfactantLung surfactantPulmonary surfactant systemAlveolar lining layerPulmonary surfactant lipid monolayer at the alveolar air–liquid interface

Exogenous surfactant replacement therapy lowers surface tension at the alveolar air-liquid interface, stabilizing the alveoli and improving gas exchange by preventing end-expiratory collapse.