Interfacial Activity of Pulmonary Surfactant Combined with Gold Nanoparticles: A Promising Tool in Lung Medicine

Abstract

Lungs epithelium is the largest surface of the human body in contact with the environment to provide the needed gas exchange for living. It is covered by Pulmonary Surfactant (PS), which is a lipid-protein complex in charge of reducing the surface tension at the air-liquid respiratory interface so minimizing the work of breathing. Thereby, collapse is avoided. Likewise PS is responsible for innate defense mechanisms preventing the entry of inhaled pathogenic entities.As a result of this lung specific design, the pulmonary route of administration is acquiring a large projection in the design of new strategies in medicine. It offers a great number of benefits in local treatment of lung diseases. In this context, Gold Nanoparticles (GNPs) seem to be a promising tool. They might improve current diagnostics and treatments due to their outstanding optical properties and ease of tuning size and shape.Since the PS layer is the first surface where NPs impinge, many studies are analyzing the influence of NPs onto the biophysical properties of PS, which will define their distribution and clearance. Therefore a deep understanding of NP-PS interaction is required as a previous step to elucidate their impact on toxicity and to develop the potential of PS as an efficient and selective vehicle of NPs.The aim of this work is to analyze the size and coating effect of GNPs, on the functional properties of native PS purified from porcine broncholveolar lavage. The interfacial activity of PS/NP combinations has been assessed by captive bubble surfactometry and surface balances. The results suggest that it is quite feasible to design GNP-PS complexes with suitable features to being used in real clinical settings.