Advancing the TIDAL Model: Integrating Sensors, Geometries, and Aerosol Types for Enhanced Lung Deposition Measurements

• Hannah Higgins, Biomedical Engineering, Mercer University

• Catherine Fromen, Chemical and Biomolecular Engineering, University of Delaware

In respiratory drug delivery, understanding spatial deposition (i.e. where the aerosol lands in the lung) is essential for optimizing treatment efficacy. Accurate assessment of spatial deposition and particle characteristics is fundamental to enhancing pulmonary drug delivery and its effectiveness in treating respiratory diseases; however, there are currently no preclinical experimental tools capable of determining that measure from an inhaled medication. The Total Inhalable Deposition in an Actuated Lung (TIDAL) model was developed in the Fromen lab as an in vitro experimental pulmonary model that can provide high-resolution spatial deposition data for the entire lung through lattice approximations for lobar surface area. While TIDAL represents a major innovation, several vital enhancements are required to heighten the TIDAL model’s capabilities, which was the focus of this project. First, it is crucial to incorporate temperature, pressure, and humidity measurements within the system. Environmental measurements are important because aerosolized particles can undergo hygroscopic growth, affecting the particles’ median mass aerodynamic diameter (MMAD) and deposition patterns. BME 280 sensors were coded and integrated into TIDAL, recording and displaying real-time regional data essential to understanding hygroscopic growth. Second, TIDAL must be adapted to simulate drug delivery in the context of obstructive lung diseases, such as asthma.  Three patient-specific airway models from Poorbahrami et al. J Appl Physiol (2019) were adapted and modified using Rhinoceros 3D and Grasshopper software to integrate into the TIDAL platform. Finally, TIDAL must accommodate a wide range of aerosol physiochemical properties. Through particle generation equipment and varied salt concentration, sodium chloride was aerosolized into precise particle size distributions and quantified through conductivity measurements, providing a simple, high-throughput readout. With all of the modifications made, the TIDAL model now is able to provide more descriptive information about spatial particle deposition while also providing more information about deposition in obstructive diseases.