Fig 1.
(a) Particle number concentration (PNC) as a function the puff duration.
Particle number was determined by Condensation Particle Counter (CPC).
Fig 2.
Comparison of particle size distribution of aerosol emissions from tobacco (0 and 24 mg/ml nicotine) and menthol (0 and 24 mg/ml nicotine) flavored ECs.
Fig 3.
Hydrodynamic diameters of EC aerosols in different dispersing media (water or cell culture media).
Cell media 1: DMEM with fetal bovine serum. Cell media 2: EpiLife media with growth supplement. Hydrodynamic size of EC aerosols was determined using high throughput dynamic light scattering (HT-DLS).
Fig 4.
Characterization of EC aerosols impinged in water.
(A) TEM analysis of EC aerosol nanoparticles in water. (B) EDX analysis of EC aerosols that identified elemental composition of EC nanoparticles.
Table 1.
Hydrodynamic diameter of EC aerosols in different dispersing media analyzed by DLS.
Table 2.
Elemental analysis of EC aerosols by ICP-OES.
Fig 5.
Oxidative stress and cytotoxicity induced by EC aerosols in NHOKs.
(A) Intracellular GSH levels in NHOKs after exposure to EC aerosols. NHOKs were exposed to EC aerosols for 24 h and intracellular GSH levels were determined using a GSH-Glo assay. Fumed silica (100 μg/ml) was used as a positive control. *p<0.05 compared to untreated control cells. (B) Heat maps to show the dose-dependent increase in oxidative stress induced by EC in NHOKs. Conditions are the same as (A). (C) Cell viability of NHOKs after exposure to EC aerosols for 24 h was determined using ATP assay. The cell viability of the EC-treated cells was normalized to the value of non-treated control cells, for which the viability was regarded as 100%. Fumed silica (100 μg/ml) was used as a positive control. *p<0.05 compared to untreated control cells. (D&E) qPCR analysis of heme oxygenase 1 (HO-1) and nuclear factor (erythroid-derived 2)-like 2 (NRF-2) expression in NHOKs after exposure to EC aerosols. *p<0.05; ** p<0.01 compared to untreated control cells.