The oxidative potential of differently charged silver and gold nanoparticles on three human lung epithelial cell types

BACKGROUND: Nanoparticle (NPs) functionalization has been shown to affect their cellular toxicity. To study this, differently functionalized silver (Ag) and gold (Au) NPs were synthesised, characterised and tested using lung epithelial cell systems. METHODS: Monodispersed Ag and Au NPs with a size range of 7 to 10 nm were coated with either sodium citrate or chitosan resulting in surface charges from -50 mV to +70 mV. NP-induced cytotoxicity and oxidative stress were determined using A549 cells, BEAS-2B cells and primary lung epithelial cells (NHBE cells). TEER measurements and immunofluorescence staining of tight junctions were performed to test the growth characteristics of the cells. Cytotoxicity was measured by means of the CellTiter-Blue ® and the lactate dehydrogenase assay and cellular and cell-free reactive oxygen species (ROS) production was measured using the DCFH-DA assay. RESULTS: Different growth characteristics were shown in the three cell types used. A549 cells grew into a confluent mono-layer, BEAS-2B cells grew into a multilayer and NHBE cells did not form a confluent layer. A549 cells were least susceptible towards NPs, irrespective of the NP functionalization. Cytotoxicity in BEAS-2B cells increased when exposed to high positive charged (+65-75 mV) Au NPs. The greatest cytotoxicity was observed in NHBE cells, where both Ag and Au NPs with a charge above +40 mV induced cytotoxicity. ROS production was most prominent in A549 cells where Au NPs (+65-75 mV) induced the highest amount of ROS. In addition, cell-free ROS measurements showed a significant increase in ROS production with an increase in chitosan coating. CONCLUSIONS: Chitosan functionalization of NPs, with resultant high surface charges plays an important role in NP-toxicity. Au NPs, which have been shown to be inert and often non-cytotoxic, can become toxic upon coating with certain charged molecules. Notably, these effects are dependent on the core material of the particle, the cell type used for testing and the growth characteristics of these cell culture model systems

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Nano-bio Interactions

Due to there extremely small size, nanoparticles display a unique set of characteristics, which differ significantly form bigger moieties. These characteristics also shape their interaction with biological entities. There large surface-to-volume area, for instance, makes particles in the nano- and micro-range very reactive. Clubmoss spores are an example of naturally occurring microparticles

The microRNA-29 family in cartilage homeostasis and osteoarthritis

MicroRNAs have been shown to function in cartilage development and homeostasis, as well as in progression of osteoarthritis. The objective of the current study was to identify microRNAs involved in the onset or early progression of osteoarthritis and characterise their function in chondrocytes. MicroRNA expression in mouse knee joints post-DMM surgery was measured over 7 days. Expression of miR-29b-3p was increased at day 1 and regulated in the opposite direction to its potential targets. In a mouse model of cartilage injury and in end-stage human OA cartilage, the miR-29 family were also regulated. SOX9 repressed expression of miR-29a-3p and miR-29b-3p via the 29a/b1 promoter. TGFβ1 decreased expression of miR-29a, b and c (3p) in primary chondrocytes, whilst IL-1β increased (but LPS decreased) their expression. The miR-29 family negatively regulated Smad, NFκB and canonical WNT signalling pathways. Expression profiles revealed regulation of new WNT-related genes. Amongst these, FZD3, FZD5, DVL3, FRAT2, CK2A2 were validated as direct targets of the miR-29 family. These data identify the miR-29 family as microRNAs acting across development and progression of OA. They are regulated by factors which are important in OA and impact on relevant signalling pathways

Nanomedicine

Important and life-sustaining processes such as teh uptake, transport and metabolism of biologicla substances take place on cellular level in the human body. Diseases and disorders happening on this level can now be targeted with diagnostic and threapeutic tools in the nano-scaled size range

Toxicity of azo-dyes combined with TiO2 nanoparticles

Azo-dyes are organices compounds frequesntly used for food colring for example in sweets. A characteristic feature of az-=dyes is the axo-group (-N=N) as part of the chromophore. In parallel, nanoparticles (NPs) are more and more used as food additives and this, the encoubter of NPs with azo-dyes is highly likely. In particular, TiO2 NPs are inciroporated into foods under the tearm E171

Nanoparticle tracking analysis

Due to their extremely small size, nanoparticles cannot be analyses by conventional approaches such as light microscopy. To visualise particles in the nanoscale range, a combination of an ultra-microscope and a laser illumination unit has to be applied. This combinatory technique is called Nanoparticle Tracking Anlysis (NTA) and can be used of thr nalysis of particles in a size range of approximately 10 nm up to 1 μm in liquid suspension

Nano-chip for cancer diagnostics

Exosomes are vesicles with a size range of 30 to 50nm, which are secreted by a cell into its surroundings..