Pulmonary surfactant-biomimetic membranized coacervate injection for acute respiratory distress syndrome therapy.

Acute respiratory distress syndrome (ARDS) is the leading cause of respiratory failure with high morbidity and mortality. Pulmonary surfactant (PS)-based complementary therapies have exhibited potential for ARDS healing and applied as an adjunctive therapy strategy. Coacervate (Coac) has the characteristics of softness, deformability and excellent molecular enrichment properties, and has attracted extensive attention in the biomedical field. Here PS and coacervate were combined for the potential ARDS treatment. The Coac, fabricated from polyallylamine hydrochloride (PAH) and adenosine triphosphate (ATP) by simple mixing, exhibited soft droplet property and high enrichment for dexamethasone sodium phosphate (DSP). To avoid the fusion effect of membraneless coacervate and endow it with biological functions of PS, liposomes with PS-biomimetic lipid components (PS-lipo) were further introduced to construct PS-biomimetic membranized coacervate (DSP@PS-Coac). The DSP@PS-Coac demonstrated high lung targeting effect and significant penetration efficiency after intravenous injection. Furthermore, PS-lipo replenished the endogenous PS pool and facilitated the distribution of DSP in inflammatory cells in the lung. In the ARDS mouse model, PS-Coac and DSP exerted synergetic anti-inflammatory functions, via reducing the recruitment of inflammatory neutrophils and modulating macrophages into anti-inflammatory phenotype. The overall results confirmed that DSP@PS-Coac may provide a promising delivery option for the treatment of ARDS.