Changes in the Activity of the Pulmonary Surfactant after Contact with Bentonite Nanoclay Particles

Abstract

Nanoclays are used as fillers in the production of polymer nanocomposites. They contribute to improving the physical, heat and resistance properties of nanocomposites. Nanomaterials used to manufacture of modern plastics may have the harmful impact on the workers’ health. Effect of inhalation of these dopants on the important structures of breathing system remains still unrecognized. Pulmonary surfactant plays the important role in proper functioning of the respiratory system by lowering the surface tension in the alveoli. This phenomenon prevents them from collapsing in the final phase of exhalation, increases their stability and prevents pulmonary edema. It also takes part in the self-cleaning of the alveoli from inhaled and deposited aerosol particles. The aim of this study was to evaluate the influence of bentonite nanoparticles on the surface activity of the pulmonary surfactant. Pharmaceutical preparation SURVANTA (Abbott, France) was used as the substance representing physicochemical properties of natural surfactant. The preparation was diluted to concentration of 1.25 mg of phospholipids/ml with sterile physiological salt solution containing the known mass of bentonite particles. The study of surface activity during oscillations (15 min-1, 37 °C) of air bubble created in the solution of the model surfactant was conducted with the dynamic tensiometric methodusing Pulsating Bubble Surfactometer (Electronetics Corp., USA). It was found that the quantitative criteria which describe the dynamic surface properties of the pulmonary surfactant (i.e., the minimum surface tension smin, the normalized hysteresis area HAn and the stability index SI) were changed after surfactant contact with the nanoparticles. The results indicate strong influence of bentonite nanoclay on pulmonary surfactant activity. These findings correspond to the observations from studies related to the impact of other nanoparticles (e.g., of gold, diesel exhaust components, etc) on the pulmonary surfactant. It is speculated that observed effects may be associated with the development of occupational respiratory diseases.