Summary

With rapid advances in micro-fabrication and -printing processes, the development of lung-on-chip platforms is offering novel avenues for more realistic inhalation assays in pharmaceutical research, and thereby depart from traditional in vitro lung assays. As advanced models capturing the cellular pulmonary make-up at an air-liquid interface (ALI), lung-on-chips emulate both morphological features and biological functionality of the airway barrier with the ability to integrate respiratory breathing motions and ensuing tissue strains. Such in vitro systems allow importantly to mimic more realistic physiological respiratory flow conditions, with the opportunity to integrate physically-relevant transport determinants of aerosol inhalation therapy, i.e. recapitulating the pathway from airborne flight to deposition on the airway lumen. Together, these attributes pave new avenues for exploring improved drug carrier designs (e.g. shape, size, etc.) and targeting strategies (e.g. conductive vs. respiratory regions) amongst other. While technical challenges still lie along the way in rendering such in vitro platforms more widespread across the general pharmaceutical research community, significant momentum is well underway in accelerating the prospect of new in vitro gold standards.