Improving Pulmonary Nano-Therapeutics Using Helical Aerosol Streams - An In-Silico Study

The increasing prevalence of pulmonary ailments including asthma, chronic obstructive pulmonary disorder (COPD), lung tuberculosis and lung cancer, coupled with the success of pulmonary therapy has led to a plethora of scientific research focusing on improving the efficacy of pulmonary drug delivery systems. Recent advances in nanoscience and nanoengineering help achieve this by developing stable, potent, inhalable nano-size drug formulations that potentially increase dosages at target sites with significant therapeutic effects. In this study, we numerically analyze a novel methodology of incorporating helical air-nanoparticle streams for pulmonary nano-therapeutics, using a customized version of the open-source computational fluid dynamics (CFD) toolbox OpenFOAM. As nanoparticles predominantly follow streamlines, helical airflow transports them in a centralized core along the human upper respiratory tract, thereby minimizing deposition and hence waste on the oropharyngeal walls, potentially also reducing the risk of drug-induced toxicity in healthy tissues. Advancing our previous study on micron-particle dynamics, helical streams are shown to improve the delivery of nanodrugs, to deeper lung regions when compared to a purely axial fluid-particle jet. For example, an optimal helical stream featuring a volumetric flow rate of 30 l/min, increased the delivery of 300 nm-particles to regions beyond generation 3 by 5%, in comparison to a conventional axial jet. Results from regional deposition studies are presented, to demonstrate the robustness of helical flows in pulmonary drug delivery; thus, paving the way towards successful implementation of the novel methodology in nanotherapeutics.