Haemolytic activity of soil from areas of varying podoconiosis endemicity in Ethiopia

Background: Podoconiosis, non-filarial elephantiasis, is a non-infectious disease found in tropical regions such as Ethiopia, localized in highland areas with volcanic soils cultivated by barefoot subsistence farmers. It is thought that soil particles can pass through the soles of the feet and taken up by the lymphatic system, leading to the characteristic chronic oedema of the lower legs that becomes disfiguring and disabling over time. Methods: The close association of the disease with volcanic soils led us to investigate the characteristics of soil samples in an endemic area in Ethiopia to identify the potential causal constituents. We used the in vitro haemolysis assay and compared haemolytic activity (HA) with soil samples collected in a non-endemic region of the same area in Ethiopia. We included soil samples that had been previously characterized, in addition we present other data describing the characteristics of the soil and include pure phase mineral standards as comparisons. Results: The bulk chemical composition of the soils were statistically significantly different between the podoconiosis-endemic and non-endemic areas, with the exception of CaO and Cr. Likewise, the soil mineralogy was statistically significant for iron oxide, feldspars, mica and chlorite. Smectite and kaolinite clays were widely present and elicited a strong HA, as did quartz, in comparison to other mineral phases tested, although no strong difference was found in HA between soils from the two areas. The relationship was further investigated with principle component analysis (PCA), which showed that a combination of an increase in Y, Zr and Al2O3, and a concurrent increase Fe2O3, TiO2, MnO and Ba in the soils increased HA. Conclusion: The mineralogy and chemistry of the soils influenced the HA, although the interplay between the components is complex. Further research should consider the variable biopersistance, hygroscopicity and hardness of the minerals and further characterize the nano-scale particles

Real-Time Nanoparticle–Cell Interactions in Physiological Media by Atomic Force Microscopy

Particle–cell interactions in physiological media are important in determining the fate and transport of nanoparticles and biological responses to them. In this work, these interactions are assessed in real time using a novel atomic force microscopy (AFM) based platform. Industry-relevant CeO2 and Fe2O3 engineered nanoparticles (ENPs) of two primary particle sizes were synthesized by the flame spray pyrolysis (FSP) based Harvard Versatile Engineering Nanomaterials Generation System (Harvard VENGES) and used in this study. The ENPs were attached on AFM tips, and the atomic force between the tip and lung epithelia cells (A549), adhered on a substrate, was measured in biological media, with and without the presence of serum proteins. Two metrics were used to assess the nanoparticle cell: the detachment force required to separate the ENP from the cell and the number of bonds formed between the cell and the ENPs. The results indicate that these atomic level ENP–cell interaction forces strongly depend on the physiological media. The presence of serum proteins reduced both the detachment force and the number of bonds by approximately 50% indicating the important role of the protein corona on the particle cell interactions. Additionally, it was shown that particle to cell interactions were size and material dependent

Box and whisker plot for normalised HA for the soil samples from podoconiosis-endemic, -non-endemic and areas with unknown endemicity.

<p>Box and whisker plot for normalised HA for the soil samples from podoconiosis-endemic, -non-endemic and areas with unknown endemicity.</p

Summary of the particle size data for the soil samples, presented for all soil samples together and by endemicity.

<p>Summary of the particle size data for the soil samples, presented for all soil samples together and by endemicity.</p

Summary of the chemistry and mineralogy of the soils, presented for all soil samples together and by endemicity.

<p>Summary of the chemistry and mineralogy of the soils, presented for all soil samples together and by endemicity.</p

Potential nanoparticle penetration routes through the skin.

<p>A) 1) via broken epidermis, 2) intercellular route, 3) transappendageal route via hair follicles (or sweat ducts) and 4) intracellular route (modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177219#pone.0177219.ref010" target="_blank">10</a>]) B) magnified schematic of a silica nanoparticle in the capillary, showing example surface features that are thought to contribute to HA in vitro.</p

HA of the soil samples (shown in terms of their endemicity) and PPRMs, presented as the slope of the HA normalised to DQ12.

<p>9A) shows the haemolysis curve for two selected samples.</p

Summary of the characteristics of the pure-phase reference minerals used in this study, including specific surface area (SSA), particle size (in water and deflocculant), Zeta Potential (ζ) and the haemolytic potential (given as the slope of absorbance versus soil suspension concentration).

<p>Summary of the characteristics of the pure-phase reference minerals used in this study, including specific surface area (SSA), particle size (in water and deflocculant), Zeta Potential (ζ) and the haemolytic potential (given as the slope of absorbance versus soil suspension concentration).</p