Abstracts from The International Society for Aerosols in Medicine 23rd ISAM Congress Boise, Idaho May 22–26, 2021

Abstract

Journal of Aerosol Medicine and Pulmonary Drug DeliveryAhead of Print AbstractsFree AccessAbstracts: International Society for Aerosols in Medicine 23rd ISAM Congress Boise, Idaho May 22–26, 2021Published Online:19 Aug 2021https://doi.org/10.1089/jamp.2021.ab02.abstractsAboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail Abstracts: 23rd ISAM Congress01. Effective Removal of Exhaled Virus Using a Viral Filter on the Aerogen Ultra Nebuliser SystemRonan MacLoughlin,1,2,3 Mary Joyce,1 and Daniel O'Toole41Aerogen, IDA Business Park, Dangan, Galway, Ireland.2School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons, Dublin, Ireland.3School of Pharmacy and Pharmaceutical Sciences, Trinity College, Dublin, Ireland.4School of Medicine, National University of Ireland Galway, Galway, Ireland.Introduction: In response to the ongoing COVID‐19 pandemic, expert consensus suggests that connection of a filter to nebulisers has the potential to mitigate the risk of bystander exposure to patient‐derived bioaerosol. Here we assess the feasibility of removing exhaled virus using a viral filter and determine its effect on nebuliser performance.Materials and Methods: Simulated exhaled breath, containing Adenovirus (Ad5‐GFP) as a tracer bioaerosol was generated during normal adult breathing (15BPM, Vt 500mL, I:E 1:1). At ∼100nm, Ad5‐GFP is similar size to SARS‐CoV‐2. Two viral filters (303EU; Vyaire, US) were connected to the mouthpiece of the Aerogen Ultra (Aerogen, Galway, Ireland). The primary filter was used to capture exhaled aerosol, the secondary to assess if virus escaped from the primary filter. Inhaled dose was assessed using salbutamol (2.5mL of 2.5mg/mL). No supplemental oxygen was used. QPCR was used to determine presence of viral plasmid on the filter. UV spectrophotometry was used to quantify salbutamol. Testing was completed in triplicate.Results: For all tests, virus was detected on the primary filter with none detected on the secondary filter. Inhaled dose was recorded as 65.22 ± 1.2 % versus 65.98 ± 2.01 % (p > 0.05), unfiltered and filtered, respectively.Conclusion: Connection of a viral filter was seen to effectively remove virus from the simulated exhaled breath, with the use of the filter not having a significant effect on nebuliser performance.02. Differential Inflammatory and Toxic Effects in Vitro of Wood Smoke and Traffic‐Related Particulate Matter from Sydney, AustraliaBaoming Wang,1,2 Hui Chen,1 Dia Xenaki,2 Jiayan Liao,3 Christine Cowie,2,4,5 and Brian G. Oliver1,21School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.2Woolcock Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.3Institute for Biomedical Materials and Devices, Faculty of Science, University of Technology Sydney, New South Wales, Australia.4South West Sydney Clinical School, University of New South Wales, Liverpool, New South Wales, Australia.5Ingham Institute of Applied Medical Research, Liverpool, New South Wales, Australia.Background: PM2.5 generated by traffic or burning wood is pro‐inflammatory and induces various adverse health outcomes in humans. In Australia, the main anthropogenic contributors to particulate matter (PM) air pollution are wood combustion heaters, on‐road vehicles, and coal‐fired power stations. However, the relative toxicity of these local sources has not to date been investigated.Method: PM2.5 was collected on filters from the same sampling site in Liverpool, Sydney. According to the positive matrix factorization and collection season, filters were representative of either day with high traffic‐related air pollution (TRAP), wood smoke, or both TRAP and woodsmoke (mixed air pollution). The elemental composition of the PM was assessed by accelerator‐based ion beam analysis techniques (i.e. PIXE & PIGE) and size by Dynamic Light Scattering. Toxicity and inflammation were assessed in‐vitro in human bronchial epithelial cells by measuring interleukin‐6 (IL‐6), interleukin‐8 (IL‐8) release, and MTT.Results: Mixed air pollution (TRAP/wood smoke) PM had more nanometre‐sized PM than the other two groups. The mixed air pollution PM was the most toxic, whereas the PM from woodsmoke induced greater IL‐6 release than TRAP PM. There was no difference in the induction of IL‐8 between the three sources of PM.03. Respirator Filtration Efficiency Before and After Decontamination by Moist Heat Incubation: Particle Size DependenceSolbee Seo, Conor A. Ruzycki, Bailey Johnson, Hui Wang, Reinhard Vehring, Dan Romanyk, Warren H. Finlay, and Andrew R. MartinDepartment of Mechanical Engineering, Faculty of Engineering, University of Alberta, Edmonton, Canada.The decontamination and reuse of respirators have been proposed to mitigate the shortage of N95 or similar high‐efficiency respirators during pandemics. The NIOSH respirator filtration efficiency (FE) test protocol defined in 42 CFR Part 84 Subpart K has been used to verify if decontamination procedures can maintain a minimum FE above 95% for some respirators. However, the defined size range of sodium chloride test aerosol is limited and may not include the most penetrating particle size for all respirators. Here, FE was measured for N95 and KN95 respirators before and after ten decontamination cycles by moist heat incubation (MHI). A custom‐designed setup was used to determine the size‐specific FE for particle aerodynamic diameters between 0.07 and 1.97 μm. For two of the three respirators tested, FE was not reduced at any size after ten cycles of MHI. For the third respirator, FE was below 95% before MHI cycles and decreased to 81% after MHI cycles. The most penetrating particle size for this respirator was outside the range defined in NIOSH protocol and further increased after MHI cycles. From this study, it is recommended that a wider test particle range, including particle sizes up to the micrometer size range, should be used when testing the FE of respirators and facemasks used during pandemics. The risk of disregarding respirator performance at larger sizes is notable in the context of filtering infectious aerosols where infectious load increases with size.04. Modulation of Allergic Airways Disease Employing Bio‐Mimetic Nanocarriers with TLR AgonistsScalise, Melanie,1,2 Ferrié, Céline,1,2 Mutlu, Seyran,1,2 Amacker, Mario,1,3 Wotzkow, Carlos,2 Steiner, Selina,2 von Garnier, Christophe,4 and Blank, Fabian1,21Respiratory Medicine, Bern University Hospital, Bern, Switzerland.2Department of BioMedical Research (DBMR), University of Bern, Bern, Switzerland3Mymetics SA, Vaud, Switzerland.4Pneumology Division, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.Allergic asthma is characterized by airway hyperresponsiveness due to a maladaptive Th2/Th9/Th17 immune response against innocuous environmental substances. Current treatments only manage to reduce the symptoms but do not alter the natural course of the disease. We aim to design and characterise the effects of bio‐mimetic nanoparticles in a mouse model of experimental allergic inflammatory airways disease (EAIAD) to skew the immune response towards Th1 polarization. We established a reproducible EAIAD mouse model showing eosinophilia and enhanced IgE titre, ready to treat allergic response with liposomes/virosomes conjugated with OVA and a TLR7/8 agonist, followed by monitoring specific immune effects. Immune cells in different lung compartments (flow cytometry), as well as lung function (Flexivent SystemTM) and IgE titre (ELISA) were monitored before and after treatment. Lung function data revealed that treatment with OVA‐liposomes rescued animals from impaired lung function, such as enhanced airway resistance, reduced forced expiratory volume in 0.1 second, reduced peak expiratory flow, enhanced IgE levels in serum. Flow cytometry analysis of pulmonary immune cells following treatment is in progress. Our results show that virosomes/liposomes ameliorate hallmarks of allergic airways disease. Bio‐mimetic nanoparticles employed as carriers for antigen and adjuvant show great potential as future therapeutic approaches for re‐programming allergic airways disease.05. Real‐time Resistance Monitoring of Human Lung Epithelial Tissue Models for Predictive Aerosol ResearchBedia Begum Karakocak,1 Gowsinth Gunasingam,1 Silvia Angeloni,2 Adrian Auderset,3 Alke Petri‐Fink,1 and Barbara Rothen‐Rutishauser11BioNanomaterials Group, Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland.2SiMPLInext SA, Rue Fritz‐Oppliger 18, 2504 Biel/Bienne, Switzerland.3Switzerland Innovation Park Biel/Bienne, Aarbergstrasse 46, 2503 Biel/Bienne, Switzerland.Numerous lung cell models have been described to simulate the human lung tissue barrier for studying the interactions of aerosolized materials with cells. These in vitro models are typically assembled on semi‐permeable inserts consisting of two‐chamber compartments. The readiness of such cell models for transport studies and drug efficacy tests is typically assessed with transepithelial/endothelial resistance (TEER) measurements of tight junctions along with permeability assays. In this study, we will present a smart silicon nitride microporous permeable insert [SiMPLI] combined with single‐frequency impedance measurements to assess resistance values of selected cells in a non‐invasive digital platform. We validated the system using human alveolar epithelial type II (A549) cell line and compared cell growth, TEER, and permeability of fluorescein isothiocyanate with cells grown on polyethylene terephthalate (PET) inserts to SiMPLI. The preliminary results showed that with SiMPLI inserts, the standard error among the technical replicates was significantly lower than the measurements obtained on conventional PET inserts. Finally, a human alveolar 3D model composed of A549 and EA.hy926 cells, along with two types of immune cells: human monocyte‐derived macrophages and dendritic cells, will be assembled simulating the lung tissue barrier. We demonstrated the superiority of the SiMPLI system as a reliable platform for real‐time monitoring of resistance in human lung cell models.06. Model‐Based Investigation of Infectious Aerosol Generation by Non‐Invasive Supplemental Oxygen Delivery Devices in Use with Covid‐19 PatientsNathaneal A. Park,1 Paul S. Soma,1 Jhaymie Cappiello,2 Kamrouz Ghadimi,2 and Gary L. Glish11University of North Carolina at Chapel Hill.2Duke Medical School.The COVID‐19 pandemic, caused by the virus SARS‐cov‐2, has been serious global health crisis. A common symptom in patients with severe cases of COVID‐19 is dangerously low blood oxygen levels. Treatment of low blood oxygen requires supplementary oxygen delivery using external means, including noninvasive nasal cannulae, rebreathing masks, and non‐ invasive ventilators (NIV devices), and in severe cases anesthesia and invasive intubation with ventilation. Though effective, invasive intubation is dangerous due in part to the application of anesthetic, and intubated patient outcomes tend to be poor. NIV devices would thus be preferable when patients exhibit only modest symptoms. However, unknowns still exist surrounding whether or not NIV oxygen delivery methods produce potentially infectious virus‐containing aerosols. Invasive ventilation involving intubation is a completely closed system and is treated as aerosol‐free and less likely to spread infection. Thus, the choice of whether to prioritize the health of patients or healthcare workers has been a dilemma. Current work has explored the possibility that dangerous amounts of aerosol are produced by noninvasive oxygen delivery devices via a mannequin simulating a patient by detecting aerosol under various parameters. Preliminary data shows the efficacy of this mannequin model as well as evidence that noninvasive ventilation may produce more aerosol than nasal cannulae or a control.07. No Evidence that Electrostatic Charge Near High Voltage Power Lines Increases the Deposition of Inhaled Ultrafine Environmental Particles in Human LungsM. Biddiscombe,1 J. Matthews,2 M. Wright,2 S. Meah,1 R. Underwood,1 P. Barnes,1 D. Shallcross,2 and O. Usmani11Imperial College London and Royal Brompton Hospital, London, United Kingdom.2University of Bristol, Bristol, United Kingdom.Background: Aerosol particles that are inhaled from the environmental air, (natural and industrial sources) may result in the deposition of potentially harmful particulate substances in the human airways. The mainly combustion‐generated submicron (1 μm) and “ultrafine” (100 nm) fractions of particles are increasingly implicated as a risk to health because of their higher number and surface area per unit mass, and their deeper lung penetration. Data showing an increase in adult and childhood leukaemia risk near to high‐voltage overhead power lines (HVPL) but beyond the range of the direct effects of electric or magnetic fields have been reported. One explanation is corona ions emitted by the power lines electrostatically charge ultrafine particles of air pollution through contact with them. This process may therefore increase the deposition fraction of charged particles relative to neutral particles in the lungs. Increased knowledge of the behaviour of charged particles in the airways is therefore crucial to the understanding of their potential impact on human health. This is the first study to clearly examine the effects of electric charge, of the same order of magnitude found near to HVPLs, on carbonaceous particulates smaller than 300 nm in the human lungs.Aim: Our hypothesis for this investigation was that particles with excess electric charge have a higher likelihood of human lung deposition than 'non‐charged ' particles.Methods: We developed and characterized a system for the generation and delivery of TechnegasTM (Cyclomedica) particles, labelled with the radionuclide Technetium‐99m (99mTc) to investigate the lung deposition of positively (CP) and neutrally charged (CN) 100nm particles. Eight healthy, non‐smoking participants (five females and three males; mean age, 33 yrs.) with normal spirometry (mean FEV1, 91.9% predicted) participated in the study. The primary outcome measure was penetration index (PI), a measure of aerosol lung deposition and penetration relative to an inert radioactive gas Krypton‐81m (81mKr). The particle number deposition efficiency (DFp) was also measured.Results: PI and DFp were indistinguishable for charged and uncharged particles (Table). This implies that the mechanism of electrostatically enhanced deposition did not measurably influence particle lung deposition in adults. These results are contrary to the corona ion hypothesis.Conclusion: The study found no evidence that charge leads to increased lung deposition in 100 nm particles suggesting that corona ions from HVPL may not be an important contributing factor influencing adult and childhood leukaemia risk.Measurement Mean (SD)PICN0.92 (0.07) CP0.92 (0.07)DFP (%)CN23.3 (4.7) CP23.3 (2.9)08. A Pneumocyte‐Like Monoclonal Cell Line to Reliably Model the Human Air‐Blood Barrier in VitroPatrick Carius,1,2 Klaus Urbschat,3 Nicole Schneider‐Daum,1 and Claus‐Michael Lehr1,21Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS), Department of Drug Delivery (DDEL), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany.2Biopharmaceutics and Pharmaceutical Technology, Saarland University, Department of Pharmacy, 66123 Saarbrücken, Germany.3Section of Thoracic Surgery of the Saar lung center, SHG clinics Völklingen, Saarbrücken, Germany.Given the delicate features of the respiratory region of the human lung, mimicking the air‐blood barrier with cell‐based in Vitro models of alveolar epithelial cells is a demanding task. Ensuring standardization and reliability of such models is recognized by the research community as an important task to generate more predictive alveolar tissue models in the future. We here report the development and characterization of a novel sub clone of the human alveolar epithelium lentivirus immortalized (hAELVi) cell line, with enhanced physiological and morphological characteristics. The sub clone was established via a single‐cell printing method and systematically compared in Vitro to primary human alveolar epithelial cells (hAEpCs) as well as to the parent hAELVi cell line with electrophysiological, morphological and cell biological techniques. After 14 days of culture, the monoclonal cell line showed high transepithelial electrical resistance (TEER) of ∼3000 Ω*cm2 and a potential difference (PD) of ∼30 mV under air‐liquid interface (ALI) conditions while simultaneously preserving monolayer‐like morphology confirmed via computational image analysis of confocal microscopic data. RNA‐sequencing analysis further showed similar expression of type 1 and type 2 pneumocyte specific transcripts between hAEpCs and the monoclonal cell line. The stability of the cell line in terms of physiological as well as morphological properties could be confirmed for more than 20 consecutive passages.09. An Easy Access Microfluidic Model for Testing Aerosolized Drugs on Pulmonary EpitheliaPatrick Carius,1,2 Aurélie Dubois, Morvarid Ajdarirad,2 Arbel Artzy‐Schnirman,3 Josué Sznitman,3 Nicole Schneider‐Daum,1 and Claus‐Michael Lehr1,21Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS), Department of Drug Delivery (DDEL), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany.2Biopharmaceutics and Pharmaceutical Technology, Saarland University, Department of Pharmacy, Saarbrücken, Germany.3Department of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa, Israel.Microfluidic lung‐on‐chips are micron‐sized, biomimetic devices that allow the in vitro culture of lung specific cell types under physiological stimuli like perfusion or air liquid interface (ALI) conditions. In an effort to combine the advantages of well‐based filter supports, like the traditional Transwell®, with the virtues of microfluidic perfusion, we here present a versatile microfluidic platform to assess barrier permeability of and aerosol deposition on ALI grown pulmonary epithelial cells. The microfluidic platform was specifically designed to be produced and implemented by biopharmaceutical and cell biological laboratories without specific expertise in microfabrication methods and without the need to buy expensive additional equipment. In a proof‐of‐concept study, Calu‐3 cells cultured under liquid covered conditions (LCC) inside the platform showed similar development of transepithelial electrical resistance (TEER) over a period of 14 days as cells cultured on a traditional Transwell®. Fluorescein sodium was nebulized by the use of an Aerogen® Solo nebulizer connected to a customized deposition chamber onto Calu‐3 cells cultured under ALI conditions. Molecular transport of fluorescein sodium was investigated under dynamic flow as well as under static transport conditions. By making the building instructions for the platform as well as all needed accessories for reproducing the experiments described here publicly accessible, we encourage the concept of open science.10. A Universal Approach for Inhalation Exposure Assessment for Bystanders During Inhalation of Therapeutic AerosolsK. Schwarz1 and R. Dhand21Division of Chemical Safety and Toxicology, Fraunhofer Institute for Toxicology and Experimental Medicine, 30625 Hannover, Germany.2Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA.The risk of unintended inhalation of therapeutic aerosols is a topic of interest in the healthcare area. However, only a few studies have characterized the risk of bystander exposure during administration of inhalation therapies so far. More comprehensive research that allows for a better understanding of influencing factors and recommendations for healthcare workers and other bystanders is of importance. Therefore, an approach providing estimates of inhalation exposure towards therapeutic aerosols has been established based on the determination of the aerosol release potential, i.e. the aerosol source strength, in combination with exposure modelling. The source strength for the release of inhalable aerosols is quantified in control measurements carried out under representative conditions. These data are used as input parameters in a newly developed deterministic exposure model to predict spatial and temporal inhalation exposure concentration profile in indoor environments. The model considers the main relevant mechanisms ‐ dispersion, evaporation, sedimentation and removal by air exchange. Comparison of the results obtained from the control measurements and the model calculations with data measured in the field show good agreement. In conclusion a practical and easy‐to‐use approach allowing for the assessment of exposure to bystanders as well as analysis of potential influencing parameters during administration of inhalation therapies has been successfully developed.11. Oxidative Stress Damage in Human Pulmonary Cells Following Titanium Dioxide Particulate ExposureJordan A. Hoops1 and Timothy M. Brenza1,21Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology.2Program of Biomedical Engineering, South Dakota School of Mines and Technology.Fine particulate matter (PM2.5) is a major health concern, impacting the respiratory system through impaired lung function, infection, cancer, and contributing to 4.2 million deaths globally in 2016. Exposure to particulate matter causes oxidative stress through the direct introduction of exogenous ROS and compounds that drive free radical reactions, or indirectly through the recruitment and activation of inflammatory cells which release free radicals. Titanium dioxide nanoparticles are widely used in industrial and consumer products including paints, plastics, pharmaceuticals, cosmetics, and food products and contribute to PM2.5. TiO2 nanoparticle toxicity has been studied extensively in dermal models, however, respiratory effects and oxidative damage pathways remain a concern. The goal of this work was to characterize the oxidative stress response of human pulmonary cell line A549 to titanium dioxide nanoparticles by chemokine production, apoptosis progression, and ratio of reduced and oxidized glutathione. Next, an antioxidant formulation was developed to prevent oxidative stress damage to the pulmonary cells when exposed to TiO2.12. Respiratory Hazards from Biomass Cooking in the Shiselweni Region of EswatiniMelinda Neumann,1Kuo‐Pin Yu,1, 2 Wen‐Chi Pan,1,2 and Shih‐Chun Candice Lung31International Health Program, National Yang Ming Chiao Tung University.2Institute of Environmental and Occupational Health Sciences, National Yang Ming Chiao Tung University.3Research Center for Environmental Changes, Academia Sinica.Smoke emission from biomass fuels is an important source of indoor air pollution, which contains pollutants that are detrimental to health. In Eswatini, 62.3% of the households still rely on solid fuel for cooking, especially wood (61.8%). However, a quantitative exposure assessment study is not available in Eswatini. Therefore, this study aims to monitor carbon monoxide (CO) and carbon dioxide (CO2) concentration during cooking hours and to assess cancer and non‐cancer risk from the exposure of particulate bound polycyclic aromatic hydrocarbons (PAHs) during cooking hours for cooking personnel in households cooking indoor using biomass fuel in the Shiselweni region. Real‐time monitoring of CO and CO2 and sampling of particulate matter was conducted in seventeen kitchens during cooking hours in the Shiselweni region among homesteads using different cooking methods: biomass in open fire, biomass stove, liquid petroleum gas stove and electric stove. Concentrations of particulate matter with aerodynamic diameter smaller than 2.5 μm (PM2.5) and 10 μm (PM10), and CO were reported to exceed the indoor exposure guideline in homesteads using biomass fuel. Moreover, from the evaluation of particulate PAHs intake concentration; biomass fuel users were reported to have a high risk of cancer (incremental lifetime cancer risk >10−5) and embryo or fatal survival (hazard quotient >1) from particulate PAHs exposure.13. Acute Effect of E‐Cigarette (EC) Inhalation on Mucociliary Clearance (MC) in EC UsersWilliam D. Bennett, Phillip W. Clapp, Kirby L. Zeman, Jihong Wu, Brian Ring, and Ilona JaspersCenter for Environmental Medicine, Asthma, and Lung Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.Introduction: Recent studies show e‐cigarette (EC) users have increased rates of chronic bronchitic symptoms that may be associated with depressed mucociliary clearance (MC). However, little is known about the acute or chronic effects of EC inhalation on in‐vivo MC.Methods: In Vivo MC was measured in young adult vapers (n = 5 males, mean age = 21) following controlled inhalation of a radiolabelled (Tc99m‐sulfur collloid) aerosol (9.5 um MMAD at a slow 0.08 L/sec inhalation flow rate). Whole‐lung clearance was measured over a 90‐min period post‐radioaerosol inhalation for baseline MC and associated with periodic vaping over the first 60 minutes of MC measurements. A controlled vaping challenge was administered at 10 min intervals and consisted of 1 puff every 30 sec for 5min from a 4th generation box mod EC containing unflavored e‐liquid (65% propylene glycol/35% vegetable glycerine, 3mg/ml nicotine).Results: Compared to baseline, whole lung average clearance (%) over the 90 min of MC measures was enhanced after EC challenge, 15 (±14) vs. 27 (±17) respectively (P < 0.05 by Wilcoxon signed‐rank test).Conclusions: Acute enhancement of in Vivo MC following EC challenge is contrary to recent in Vitro studies showing slowed or no change in ciliary beat and mucus transport. However, our findings are consistent with an acute increase in fluid volume to the bronchial airway surface, similar to what is seen with inhaled hydration therapies such as hypertonic saline. Supported by NIH R01HL139369.14. 3D Immunocompetent in Vitro Lung Models Provide Mechanistic Understanding for Inhaled Safety AssessmentsMartin, A.,1,2 Hoffman, E.,2 Perez‐Diaz, N,2 Mahendran, R.,1 Saeed, A.,2 and Hutter, V.1,21Centre for Topical Drug Delivery and Toxicology, University of Hertfordshire, Hatfield, Herts, United Kingdom.2ImmuONE Ltd, Science Building, College Lane, Hatfield, Herts, United Kingdom.The fate of inhaled particles and ability to predict interactions that determine lung health largely remain unknown. It is well established that alveolar macrophages are the first line of defense against inhaled particulates in the respiratory airways. One third of inhaled medicines fail in pre‐clinical in Vivo studies due to the presence of abnormal alveolar macrophage morphology. However, it is unclear if these alveolar macrophage responses affect health and their relevance to humans. The aim of this work was to establish a robust human in vitro, 3D immunocompetent model of the alveolus to evaluate the responses of alveolar macrophages and to ascertain if this could provide a more accurate and mechanistic‐driven prediction of inhaled safety assessment. A 3D immunocompetent model of the alveolus (ImmuLUNGTM) was constructed and optimized such that it maintained functionality and viability of both epithelial and immune cell types for over 3 weeks. High‐content image analysis was used to assess detailed morphological and health descriptors of individual alveolar macrophage‐like cells within the model after exposure to a panel of inhaled medicines and control compounds. Phenotype profiling of cell responses was highly reproducible and allowed detailed mechanistic insight into the degree of adversity of the response. This approach has provided new insights to the mechanistic understanding of the fate of inhaled substances in human lungs to support toxicity assessment.15. Quantification of Exhaled Particles for the Identification of Airborne Infection Risks in SARS‐CoV2 and Assessment of Protective MeasuresKatharina Schwarz,1 Wolfgang Koch,1 Florian Fiedler,1 Horst Windt,1 Nadja Struß,1 and Jens Hohlfeld1,2,31Fraunhofer Institute for Toxicology and Experimental Medicine, 30625 Hannover, Germany.2Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany.3Member of the German Center for Lung Research (DZL‐BREATH), Hannover, Germany.Research is being conducted to assess and reduce the risk of infection by viruses transmitted via aerosols in enclosed spaces. This includes the development of simulation‐based methods requiring the input of exhaled droplet characteristics. Though a number of studies are available for different respiratory activities, there is a lack in data regarding the assessment of the complete size spectrum relevant for aerosol transmission as well as on aerosol release data during realistic use of masks. Therefore a new set–up has been established allowing for the quantitative collection and analysis of respiratory aerosols over a wide size range from 0.1 ‐ ∼ 80 μm under realistic conditions as well as under use of masks. Exhaled particle flux, size distribution and breathing patterns are determined for normal tidal breathing, speaking, coughing and singing in healthy volunteers (n = 30) by means of two laser particle spectrometers (PMT Lasair III‐110, Lighthouse Boulder Counter). This allows for a quantitative assessment of the particles relevant of the airborne transmission and the determination of the efficacy of medicinal and community masks regarding particle retention under realistic conditions. Based on these data and in combination with exposure