Submicron particle deposition in pulmonary alveoli during cyclic breathing

The prediction of deposition efficiency of submicron particles in the pulmonary alveoli has received special attention due to its importance for drug delivery systems and for assessing air pollutants health risks. in this work, the pulmonary alveoli of a healthy human are idealized by a three-dimensional honeycomb-like configuration and a fluid-structure interaction analysis is performed. in contrast to previous works in which the inlet flow rate is predefined, in this model, a negative pressure is imposed on the outside surface of the alveolus which causes air to flow in and out of the alveolus. the resulting flow patterns confirmed that there was no circulation in the terminal alveolus. the predicted alveolar airflow was used to calculate the trajectories of submicron particles using the lagrangian approach. our findings suggest that an accurate simulation requires including at least ten breathing cycles, considering a parabolic radial distribution of injected particles and continuous injection. the presented results show high deposition efficiency for submicron sizes in the alveolar region if these particles can reach the alveolar region. therefore, the vesicles technology in which particle agglomerates would be released after the vesicle reaching the alveoli is suggested for targeted drug delivery to the alveolar region.