Breathe Easy

Lung model to study particle inhalation and deposition

The acinus-on-chip developed at Technion

Our lungs represent a prodigious organ for exchange with an intricate network of airways connecting a vast airspace, from the trachea down to the individual alveoli (less than 1 mm big). With each breath, we potentially inhale millions of particles into our lungs. Understanding the basic mechanisms governing the transport of inhaled particles in the deep alveolated regions called acini, is important both in health risk assessment (occupational and environmental exposure, for example) and inhalation therapy (such as delivering vaccines or antibiotics).

To date, however, no diagnostic tool or imaging modality exists to measure in vivo the dynamics of airborne particles and their trajectories in the pulmonary acini of our lungs. It follows that much of our understanding of what precisely goes on down in the depths of the lung has mostly relied on computer-based simulations.

“This artificial-breathing 'guinea pig' not only has the potential to serve as a screening tool… such in vitro methods may also provide alternatives to animal testing.”

Technion researchers, led by principal investigator Prof. Josué Sznitman of the Faculty of Biomedical Engineering, designed an in vitro platform for studying the dynamics of inhaled particles and ensuing deposition patterns inside pulmonary acini. Using microfluidic technology, they have constructed a true-scale pulmonary acinar model that allows - for the first time - direct time-resolved observation of airborne particle trajectories and mapping detailed deposition locations of aerosols.

The research paper describing this work, titled "Particle dynamics and deposition in true-scale pulmonary acinar models," was published online on September 11, 2015, in Nature Publishing Group's Scientific Reports.

(l-r) PhD student Rami Fishler and Prof. Josué Sznitman hold their patented in vitro breathing model

The acinus-on-chip platform consists of an anatomically inspired, multi-generation network of bifurcating airway ducts lined with alveolar cavities, where the walls are periodically deformed in a physiologically realistic "breathing" fashion. "This artificial-breathing 'guinea pig' not only has the potential to serve as a screening tool to quantify the fate of inhaled particles inside the lung depths, such in vitro methods may also provide viable alternatives in the future to traditional, but controversial, animal testing," says Sznitman.

The interdisciplinary research involved colleagues at the Faculty of Biomedical Engineering and the Faculty of Civil and Environmental Engineering, the Technion Center of Excellence in Environmental Health and Exposure Science (TCEEH), the Micro-Nano Fabrication Unit, and was supported by the Russell Berrie Nanotechnology Institute at Technion. In February 2015, Sznitman and his doctoral student Rami Fishler patented the device. In June 2015, Sznitman received the “Young Investigator Award” for a researcher aged less than 40 from the International Society of Aerosols in Medicine (ISAM).