Suchergebnisse

Abstract In this study, we explored the biocompatibility of Au nanoparticles (NPs) capped with peptide-biphenyl hybrid (PBH) ligands containing glycine (Gly), cysteine (Cys), tyrosine (Tyr), tryptophan (Trp) and methionine (Met) amino acids in the human hepatocellular carcinoma cell line Hep G2. Five AuNPs, Au[(Gly-Tyr-Met)2B], Au[(Gly-Trp-Met)2B], Au[(Met)2B], Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B], were synthesised. Physico-chemical and cytotoxic properties were thoroughly studied. Transmission electron micrographs showed isolated near-spherical nanoparticles with diameters of 1.5, 1.6, 2.3, 1.8 and 2.3 nm, respectively. Dynamic light scattering evidenced the high stability of suspensions in Milli-Q water and culture medium, particularly when supplemented with serum, showing in all cases a tendency to form agglomerates with diameters approximately 200 nm. In the cytotoxicity studies, interference caused by AuNPs with some typical cytotoxicity assays was demonstrated; thus, only data obtained from the resazurin based assay were used. After 48-h incubation, only concentrations ≥50 μg/ml exhibited cytotoxicity. Such doses were also responsible for an increase in reactive oxygen species (ROS). Some differences were observed among the studied NPs. Of particular importance is the AuNPs capped with the PBH ligand (Gly-Tyr-TrCys)2B showing remarkable stability in culture medium, even in the absence of serum. Moreover, these AuNPs have unique biological effects on Hep G2 cells while showing low toxicity. The production of ROS along with supporting optical microscopy images suggests cellular interaction/uptake of these particular AuNPs. Future research efforts should further test this hypothesis, as such interaction/uptake is highly relevant in drug delivery systems. ; This research was performed under the Environmental ChemOinformatics (ECO) Marie Curie Initial Training Network (ITN) programme, funded by the Seventh Research Framework Programme (FP7) of the European Union (238701). We also thank Mapfre research grants 2010, the Spanish Ministry of Economy and Competitiveness (MINECO project CTQ 2010–19295) and the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (Project AT 2011–001) for financial support. ; Peer Reviewed

Abstract
Background
This study was conducted to provide much needed information on the potential of low solubility, highly biodurable nanoparticles (NPs) (TiO2 and CeO2 NPs), to bioaccumulate in fish and to investigate the relationship between an engineered nanomaterials surface coating, uptake and biokinetics in vivo. Rainbow trout (Oncorhynchus mykiss) were fed diets spiked with uncoated or surface coated (polyethylene glycol (PEG) or citrate (CIT)) TiO2 and CeO2 NPs (100 mg NPs/kg feed) for 10 days and thereafter fish were allowed to depurate for 42 days. Special care was taken to measure the real dispersed and actual administered concentrations, taking into consideration any potential losses from leaching, and to characterise the form (size, aggregation state, charge) of the NPs to which the fish were exposed.

Results
The coatings had an influence on levels of uptake and distributions. Most notably a higher uptake of PEG and CIT coated TiO2 and CeO2 NPs compared to fish exposed to uncoated materials was observed. The elimination of any Ti from tissues was rapid during the first day of depuration, whereas Ce levels remained in fish tissues (stomach, intestine and liver) with differences in depuration and redistribution of the three types of CeO2 NPs. However, no bioaccumulation potential for both tested metal oxide NPs in fish irrespective of coatings is expected according to BMF values < 1.

Conclusions
Distinct uptake, distribution and depuration kinetics in rainbow trout have been evidenced for different metal oxide NPs (TiO2 and CeO2 NPs). Coatings influenced uptake and in some cases led to slower depuration and distinct distributions, but do not make the uncoated NPs studied bioaccumulative (BMF > 1).

Graphical Abstract