The Advanced Integrated Respiratory (AIR) model: integration of air–liquid interface cell cultures within a human airway model for inhalation toxicology

Purpose: The Advanced Integrated Respiratory (AIR) model was developed as a physiologically relevant benchtop system designed to assess aerosol deposition and interactions within the respiratory tract. Methods: This model integrates a three-dimensional (3D) cast of the human airways with a vacuum driven aerosol inhalation flow and an air liquid interface (ALI) cell culture platform. In this study, the integrated AIR and ALI cell model was used to investigate the toxicity profile of aerosolized Ricinus communis agglutinin-1 (RCA I) toxin. RCA I was characterized in terms of particle size, surface charge, rheology, and aerosol performance. Additionally, real-time electrochemical detection using the Micro Analytical Device (MAD) provided high sensitivity quantification of aerosolized RCA I. The biological effects were assessed using human epithelial cells cultured under ALI conditions, which were exposed to RCA I aerosols. Cytotoxicity and barrier function assays were performed to evaluate its impact. Results: Results show significant differences in toxic dose thresholds comparing 2D and AIR models. Transport study revealed that RCA I exhibited significantly increased mass transport across the epithelial cell layer at toxic concentrations compared to non-toxic concentrations. Conclusions: This integrated approach represents a significant advancement in the study of inhaled aerosol deposition, toxicity, and pharmacokinetics, offering a robust tool for predicting lung injury and enhancing the detection of a wide range of inhaled aerosols, including but not limited to toxins.