Fig. 2

Nanomaterial characterisation and lung deposition. CeO₂NPs were re-suspended in water, drops dried on TEM grids, and primary size and structure visualised using TEM (a). These nanoparticles were also suspended in PBS treatment diluent with and without HDM and agglomerate size was determined using nanoparticle tracking analysis (b) with results expressed as mean, mode and standard deviation (SD) of size distribution. Particle charge was also determined as zeta potential (ZP) by dynamic light scattering and expressed in millivolts (mV) mean values ± standard error of the mean (SEM) (b). Mice were exposed to CeO₂NPs at either a low dose (CeLD) (75 μg/kg) or high dose (CeHD) (750 μg/kg) with and without HDM (1.25 mg/kg), instillation protocols as described in Fig. 1. After treatment, lung tissue was removed and digested prior to ICP-MS based quantification of elemental ¹⁴⁰Ce content. Results are expressed as μg/g lung tissue mean values ± SEM for between 3 and 6 animals (c). Statistical significance between all treatments was carried out using one way ANOVA with comparison between CeHD and HDM + CeHD represented as (* p < 0.05). Lung tissue from a single exposure to CeHD for 24 h was fixed in 10% formalin and processed for laser ablation ICP-MS detection of ⁶³Cu (b, d) and ¹⁴⁰Ce (c, e) tissue distribution (d). The elemental distribution in both whole lung (a,b,c) (× 4 magnification) and airway (d,e) (× 100 magnification) was examined. H&E staining was used to visualise general lung structure (a) (d)