Interfacial rheology for the assessment of potential health effects of inhaled carbon nanomaterials at variable breathing conditions

Abstract

Lung surface is the first line of contact between inhaled carbon nanomaterials, CNMs, and the organism, so this is the place where pulmonary health effects begin. The paper analyzes the influence of several CNMs (single-and multi-walled nanotubes with various surface area: 90-1,280 m 2 /g and aspect ratio: 8-3,750) on the surface-active properties of the lung surfactant, LS, model (Survanta). Effects of CNM concentration (0.1-1 mg/ml) and surface oscillation rate were determined using the oscillating drop method at simulated breathing conditions (2-10 s per cycle, 37 °C). Based on the values of apparent elasticity and viscosity of the interfacial region, new parameters: S ε and S μ were proposed to evaluate potential effect of particles on the LS at various breathing rates. Some of tested CNMs (e.g., COOH-functionalized short nanotubes) significantly influenced the surfactant dynamics, while the other had weaker effects even at high particle concentration. Analysis of changes in S ε and S μ provides a new way to evaluate of a possible disturbance of the basic functions of LS. The results show that the expected pulmonary effects caused by inhaled CNMs at variable breathing rate depend not only on particle concentration (inhaled dose) but also on their size, structure and surface properties. Carbon nanomaterials, CNMs, are used (or can be formed as by-products) in many applications, which can be associated with an unintentional release of nanometric dust to the air 1-7. The aerosol generated in this way is respirable (inhalable) and easily penetrates to the alveolar region of the respiratory system 8,9. A substantial number of inhaled nanoparticles that are deposited in this region can promote direct interactions with the organism 10-12. The first surface met by inhaled particles in the pulmonary region is a thin layer of alveolar liquid on the top of lung epithelium. This layer contains the mixture of specific compounds of the lung surfactant, LS-the structure, which plays a vital role in the physiological functions of the respiratory system 13. It has been recognized that LS is sensitive to inhaled materials 9,14-16 , and the resulting impairment of LS composition and/or properties may contribute to serious health problems, including the acute lung injury and respiratory distress. Accordingly, the analysis of LS properties in the presence of external factors such as micro/nanoparticles or chemicals, can give a preliminary information regarding the possible respiratory health problems that may follow inhalation of these agents 17-20. Because of the high surface-to-volume ratio, inhaled nanoparticles present a particular threat for health even when their deposited mass is not high 21. As shown by the recent studies 22,23 , effect of different nanomaterials on LS system may be highly specific and depend on several particle properties, such as the specific surface area, SSA or degree of hydrophobicity. Particle dose (concentration) is another essential factor in predicting lung toxicity 24. Therefore, the current stu...

Inhaled aerosols: Their role in COVID-19 transmission, including biophysical interactions in the lungs

“…nanoparticles), have also a high deposition probability in these regions. Such particles are usually neglected in inhalation drug delivery as practically absent in aerosols generated in medical inhalers [ 24 ], however nanoparticles are extremely important regarding health effects of inhaled industrial and other anthropogenic aerosols [ 29 , 30 , 31 ]. This particle size range is also unimportant in the discussion of coronavirus aerosols as the virus itself is larger than 100 nm.…”

“…It may be speculated that such a low surface tension comes from the equilibrium value and an excess (or rather: deficit) value produced by mechanical factors. This is why the dilatational surface rheology should be considered in analyzing of these dynamic phenomena [ 31 , 79 , 80 , 81 ].

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“…Nanostructured and nanoporous particles have the largest area/volume ratio and therefore induce stronger surface effects than non-porous micrometer-size particles. When a large number of inhaled particles land on the ALI of the pulmonary region, their direct physicochemical interactions with PS may alter the natural interfacial processes of this system [ 30 , 31 , 90 ]. It should be noted, however, that some deposits are fully or partly soluble in the pulmonary liquid, e.g.…”

“…Considering the most probable inhalation scenarios, arrival of completely dry active virus particles to the surface of the lungs is unlikely. It is a quite different situation as compared to the more often discussed deposition of inhaled natural or man-made dust micro- or nanoparticles [ 28 , 31 ]. As schematically shown in Fig 5 , a droplet with SARS-CoV-2 deposited on the alveolar ALI will spread immediately and mix with the pulmonary fluid, which allows the virus to pass the air/liquid barrier formed by the surfactant more easily as compared to a dry particle that is captured on the interface [ 30 ].…”

State of the art in additive manufacturing and its possible chemical and particle hazards—review

“… 100 , 110 The significance of ultrafine particle emission is under growing suspicion in its relationship to inflammatory, pulmonary, and cardiovascular effects. 111 , 112 , 113 , 114 Ultrafine particles (below 100 nm) can penetrate the blood and biological membranes, and as a result can be translocated to different human internal organs, causing negative health effects. 115 , 116 , 117 , 118 The toxic effect of PM is believed to be associated with particles of aerodynamic diameter less than 10 μm.…”