Effects of nanoparticles on the mechanical functioning of the lung

• We review studies on how different nanoparticles interact with pulmonary surfactant.
• We analyze how three key physicochemical properties effect monolayer function.
• Each study demonstrated that nanoparticles hinder surfactant monolayer function.
• Nanoparticle size, hydrophobicity, and surface charge effects can be generalized.
• How these effects lead to health problems remains a gap in current understanding.

Nanotechnology is a rapidly expanding field that has very promising applications that will improve industry, medicine, and consumer products. However, despite the growing widespread use of engineered nanoparticles in these areas, very little has been done to assess the potential health risks they may pose to high-risk areas of the body, particularly the lungs. In this review we first briefly discuss the structure of the lungs and establish that the pulmonary surfactant (PS), given its vulnerability and huge contribution to healthy lung function, is a mechanism of great concern when evaluating potential nanoparticle interactions within the lung. To warrant that these interactions can occur, studies on the transport of nanoaerols are reviewed to highlight that a plethora of factors contribute to a nanoparticle's ability to travel to the deep regions of the lung where PS resides. The focus of this review is to determine the extent that physicochemical characteristics of nanoparticles such as size, hydrophobicity, and surface charge effect PS function. Numerous nanoparticle types are taken into consideration in order to effectively evaluate observed consistencies across numerous nanoparticle types and develop general trends that exist among the physicochemical characteristics of interest. Biological responses from other mechanisms/components of the lung are briefly discussed to provide further insights on how the toxicology of different nanoparticles is determined. We conclude by discussing general trends that summarize consistencies observed among the studies in regard to physicochemical properties and their effects on monolayer function, addressing current gaps in our understanding, and discussing the future outlook of this field of research.

Human respiratory system diagram: http://bathroom-sink.org/galery/respiratory-system-diagramAlveoli + pulmonary surfactant: https://embryology.med.unsw.edu.au/embryology/index.php/ANAT2511_Respiratory_SystemFigure optionsDownload as PowerPoint slide