Comparative analysis of the toxicity of gold nanoparticles in zebrafish

The use of nanoparticles - particles that range in size from 1 to 100 nanometres - has become increasingly prevalent in recent years, bringing with it a variety of potential toxic effects. Zebrafish embryos were exposed during the 3-day post-fertilisation period to gold nanospheres (GSSs), gold nanorods (GNRs), gold nanorods coated with polystyrene-sulfate (PSS-GNRs), and gold nanorods coated with both polystyrene-sulfate and polyallamine hydrochloride (PAH/PSS-GNRs). All nanorods were stabilised with cetyltrimethylammonium bromide (CTAB). GNSs were the least toxic of the nanoparticles studied, with exposure resulting in no significant changes in mortality, hatching or heart rate. Exposure to GNRs and PSS-GNRs resulted in significant increases in mortality and significant decreases in hatching and heart rate. Treatment with GNRs caused significant changes in the expression of a variety of oxidative stress genes. The toxic effects of GNRs were ameliorated by coating them with polystyrene-sulfate and, to a more marked extent, with a double coating of polystyrene-sulfate and polyallamine hydrochloride

Protective Ag :TiO2 thin films for pressure sensors in orthopedic prosthesis: the importance of composition, structural and morphological features on the biological response of the coatings

DC reactive magnetron sputtered Ag:TiO2 nanocomposite thin films were developed to be used as protective coatings in pressure sensor devices. The coatings, with Ag content varying from 0 to about 30 at.%, were prepared and characterized in order to study their biological response. The as-deposited samples were annealed in vacuum at 500 °C in order to evaluate the influence of their morphological and structural differences over the response elicited upon contact with simulated bodily fluids and cultured human cells, as well as selected microorganisms. The results showed that the annealing treatment produced less porous films with an enhanced structure, with a significant reduction in structural defects and improved crystallinity. Additionally, samples with higher Ag contents (≥12.8 at.%) exhibited Ag agglomerates/clusters at the surface, a result anticipated from the XRD data. The crystallization of the TiO2 matrix was also observed by XRD analysis, albeit delayed by the dispersion of Ag into the matrix. Biological characterization showed that the antimicrobial activity and cytotoxicity of the coatings were directly related with their composition, closely followed by the particular structural and morphological features, namely those resulting from annealing process.This research is partially sponsored by FEDER funds through the program COMPETE—Programa Operacional Factores de Competitividade and by national funds through FCT—Fundação para a Ciência e a Tecnologia, under the projects PEst-C/EME/UI0285/2011, PTDC/SAU-ENB/116850/2010, PTDC/CTM-NAN/112574/2009P. T Matamá acknowledges FCT for Grant SFRH/BPD/47555/2008

Synthesis, characterisation and antifungal activity of chemically and fungal-produced silver nanoparticles against Trichophyton rubrum

Aims To characterise and explore the potential in extracellular biosynthesis of silver nanoparticles (AgNPs) by Penicillium chrysogenum and Aspergillus oryzae and to investigate the antifungal effect of chemically vs. biologically synthesised AgNPs comparing with conventional antifungal drugs against Trichophyton rubrum. Methods and Results Chemically synthesised AgNPs (Chem-AgNPs) coated with polyvinylpyrrolidone (PVP) were synthesised by chemical reduction method with glucose in PVP aqueous solution. Biologically synthesised AgNPs (Bio-AgNPs) were produced from the extracellular cell-free filtrate of Penicillium chrysogenum MUM 03.22 and Aspergillus oryzae MUM 97.19. Among the commercial antifungal drugs terbinafine exhibited the lower MIC range values of 0.063 to 0.25 μg ml-1 for the clinical strains. Chem-AgNPs exhibited antifungal activity against all T. rubrum strains. Bio-AgNPs produced by the fungal cell-free filtrate of P. chrysogenum showed an antifungal activity higher than fluconazole but less than terbinafine, itraconazole and Chem-AgNPs. Conclusion The synthesis parameters in future works should be carefully studied to take full advantage of all the potential of filamentous fungi in the synthesis of AgNPs. Significance and Impact of the study: Bio-AgNPs could be used as antifungal agents, namely against dermatophytesThe authors thank Pedro Martins (Physics Department of University of Minho) for help in XRD analysis. The authors thank to SDBSWeb: http://sdbs.db.aist.go.jp (Japanese National Institute of Advanced Industrial Science and Technology). The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. Nicolina Dias acknowledges the project 'Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB', RECI/BBB-EBI/0179/2012

The Gut Microbiome and Aquatic Toxicology: An Emerging Concept for Environmental Health

The microbiome plays an essential role in the health and onset of diseases in all animals, including humans. The microbiome has emerged as a central theme in environmental toxicology, as microbes interact with the host immune system in addition to its role in chemical detoxification. Pathophysiological changes in the gastrointestinal tissue caused by ingested chemicals, and metabolites generated from microbial biodegradation, can lead to systemic adverse effects. This critical review dissects what we know about the impacts of environmental contaminants on the microbiome of aquatic species, with special emphasis on the gut microbiome. We highlight some of the known major gut epithelium proteins in vertebrate hosts that are targets for chemical perturbation, proteins that also directly cross‐talk with the microbiome. These proteins may act as molecular initiators for altered gut function, and we propose a general framework for an adverse outcome pathway that considers gut dysbiosis as a major contributing factor to adverse apical endpoints. We present two case studies, nanomaterials and hydrocarbons with special emphasis on the Deepwater Horizon oil spill, to illustrate how investigations into the microbiome can improve understanding of adverse outcomes. Lastly, we present strategies to functionally relate chemical‐induced gut dysbiosis with adverse outcomes, as this is required to demonstrate cause‐effect relationships. Further investigations into the toxicant‐microbiome relationship may prove to be a major breakthrough for improving animal and human health. This article is protected by copyright. All rights reserve