Chronic dietary toxicity of zinc oxide nanoparticles in common carp (Cyprinus carpio L.): Tissue accumulation and physiological responses.

Concerns regarding the potential toxic effects of zinc oxide nanoparticles (ZnO NPs) on aquatic organisms are growing due to the fact that NPs may be released into aquatic ecosystems. This study aimed to investigate the effects of dietary exposure to ZnO NPs on juvenile common carp (Cyprinus carpio). Fish were fed a spiked diets at doses 50 and 500mg of ZnO NPs per kg of feed for 6 weeks followed by a 2-week recovery period. Fish were sampled every 2 weeks for haematology trends, blood biochemistry measures, histology analyses, and determination of the accumulation of zinc in tissues. At the end of the exposure and post-exposure periods, fish were sampled for an assessment of lipid peroxidation levels. Dietborne ZnO NPs had no effects on haematology, blood biochemistry, and lipid peroxidation levels during the exposure period. After the recovery period, aspartate aminotransferase activity significantly (p < 0.05) increased and alanine transferase activity significantly (p < 0.05) decreased in the higher exposure group. The level of lipid peroxidation significantly (p < 0.05) decreased in liver of treated fish after 2 weeks post-exposure period. A histological examination revealed mild histopathological changes in kidneys during exposure. Our results did not show a significant increase of zinc content at the end of experiment in any of tested organs. However, chronic dietary exposure to ZnO NPs might affect kidney and liver function.

Silver nanoparticles strongly enhance and restore bactericidal activity of inactive antibiotics against multiresistant Enterobacteriaceae.

Bacterial resistance to conventional antibiotics is currently one of the most important healthcare issues, and has serious negative impacts on medical practice. This study presents a potential solution to this problem, using the strong synergistic effects of antibiotics combined with silver nanoparticles (NPs). Silver NPs inhibit bacterial growth via a multilevel mode of antibacterial action at concentrations ranging from a few ppm to tens of ppm. Silver NPs strongly enhanced antibacterial activity against multiresistant, ß-lactamase and carbapenemase-producing Enterobacteriaceae when combined with the following antibiotics: cefotaxime, ceftazidime, meropenem, ciprofloxacin and gentamicin. All the antibiotics, when combined with silver NPs, showed enhanced antibacterial activity at concentrations far below the minimum inhibitory concentrations (tenths to hundredths of one ppm) of individual antibiotics and silver NPs. The enhanced activity of antibiotics combined with silver NPs, especially meropenem, was weaker against non-resistant bacteria than against resistant bacteria. The double disk synergy test showed that bacteria produced no ß-lactamase when treated with antibiotics combined with silver NPs. Low silver concentrations were required for effective enhancement of antibacterial activity against multiresistant bacteria. These low silver concentrations showed no cytotoxic effect towards mammalian cells, an important feature for potential medical applications.

Silver Nanocoating Technology in the Prevention of Prosthetic Joint Infection.

Prosthetic joint infection (PJI) is a feared complication of total joint arthroplasty associated with increased morbidity and mortality. There is a growing body of evidence that bacterial colonization and biofilm formation are critical pathogenic events in PJI. Thus, the choice of biomaterials for implanted prostheses and their surface modifications may significantly influence the development of PJI. Currently, silver nanoparticle (AgNP) technology is receiving much interest in the field of orthopaedics for its antimicrobial properties and a strong anti-biofilm potential. The great advantage of AgNP surface modification is a minimal release of active substances into the surrounding tissue and a long period of effectiveness. As a result, a controlled release of AgNPs could ensure antibacterial protection throughout the life of the implant. Moreover, the antibacterial effect of AgNPs may be strengthened in combination with conventional antibiotics and other antimicrobial agents. Here, our main attention is devoted to general guidelines for the design of antibacterial biomaterials protected by AgNPs, its benefits, side effects and future perspectives in PJI prevention.

Reprint of: Cytotoxicity, cell uptake and microscopic analysis of titanium dioxide and silver nanoparticles in vitro.

Commercially manufactured nanomaterials are used massively for modification of products of everyday use, including products intended for children. Therefore their potential risks have to be ultimately studied. Aside from toxicity of nanomaterials with known specific parameters, the end-consumer is potentially endangered by materials with unknown specification. Commercially available products are not usually accompanied by parameter/specification sheet providing the consumer with sufficient chemico-physical parameters allowing the evaluation of possible toxic effects. The aim of this work was to evaluate the declared parameters of commercially available TiO2 and Ag NPs employing chemico-physical methods and consequently in vitro cytotoxicity and genotoxicity tests performed on non-cancer cell lines. Based on the results of our complex study we can conclude that the data provided by the producers are not in good agreement with the performed measurements. Furthermore, all tested NPs penetrated into the SVK14 cells and all NPs had significant effect on the kinetics of ROS production in all cell lines (note: the ROS production has not been established as the major mechanism of cell damage elicited by Ag NPs). The study revealed greater cytotoxic potential of Ag NPs in comparison with TiO2 NPs and all of the studied NPs caused significant DNA damage.

Cytotoxicity, cell uptake and microscopic analysis of titanium dioxide and silver nanoparticles in vitro.

Commercially manufactured nanomaterials are used massively for modification of products of everyday use, including products intended for children. Therefore their potential risks have to be ultimately studied. Aside from toxicity of nanomaterials with known specific parameters, the end-consumer is potentially endangered by materials with unknown specification. Commercially available products are not usually accompanied by parameter/specification sheet providing the consumer with sufficient chemico-physical parameters allowing the evaluation of possible toxic effects. The aim of this work was to evaluate the declared parameters of commercially available TiO2 and Ag NPs employing chemico-physical methods and consequently in vitro cytotoxicity and genotoxicity tests performed on non-cancer cell lines. Based on the results of our complex study we can conclude that the data provided by the producers are not in good agreement with the performed measurements. Furthermore, all tested NPs penetrated into the SVK14 cells and all NPs had significant effect on the kinetics of ROS production in all cell lines (note: the ROS production has not been established as the major mechanism of cell damage elicited by Ag NPs). The study revealed greater cytotoxic potential of Ag NPs in comparison with TiO2 NPs and all of the studied NPs caused significant DNA damage.