A complete cytotoxic profile of exposure to silver (AgNP) nanoparticles investigating their biological effects on the innate immune response of circulating white blood cells is required to form a complete understanding of the risk posed. This was explored by measuring AgNP-stimulated gene expression of the pro-inflammatory cytokines interleukin-1 (IL-1), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in THP-1 monocytes. A further study, on human monocytes extracted from a cohort of blood samples, was carried out to compare with the AgNP immune response in THP-1 cells along with the detection of pro-IL-1β which is a key mediator of the inflammasome complex.The aims of the study were to clearly demonstrate that AgNP can significantly up-regulate pro-inflammatory cytokine gene expression of IL-1, IL-6 and TNF-α in both THP-1 cells and primary blood monocytes thus indicating a rapid response to AgNP in circulation. Furthermore, a role for the inflammasome in AgNP response was indicated by pro-IL-1β cleavage and release. These results highlight the potential inflammatory effects of AgNP exposure and the responses evoked should be considered with respect to the potential harm that exposure may cause.

The antioxidant properties of rosemary oleoresin in precooked roast beef slices were compared to those of a butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT) combination, sodium tripolyphosphate and sodium citrate, during both refrigerated and frozen storage. Their antioxidant properties were measured by means of TBARS (TBA‐reactive substances) and sensory scores. Sodium tripolyphosphate was the most effective antioxidant during both storage periods. Rosemary oleoresin in combination with sodium tripolyphosphate proved to be effective during both storage periods, but in particular, during frozen storage at preventing an increase in TBARS and at improving the flavour preference for the roast beef slices. Sodium citrate proved to be an ineffective antioxidant. The treatments containing salt, phosphate plus BHA/BHT and salt plus BHA/BHT had comparable antioxidative properties to the treatments containing salt, phosphate and rosemary and salt and rosemary, respectively. No overall significant correlation coefficients were obtained between the TBARS and the sensory scores. © 1998 SCI.

a b s t r a c tHypothesis: Metallic nanoparticles such as nano-silver have found many applications as alternative antimicrobials in recent years. However methods for determining their proposed antimicrobial activity have received little attention to date. The disk diffusion assay is commonly used as a demonstration of antimicrobial properties and is a regular feature in synthetic nanoparticle papers. The aim of this study was to assess its effectiveness in demonstrating the ''nanoparticle specific'' antimicrobial properties in the absence of ionic contributions from unreacted reducing agents and or impurities. Experiments: The disk diffusion assay was carried out on a range of silver nanoparticles, both in-house synthesised and commercially available, using Escherichia coli ATCC 25922 as a model organism. Results: Capped and purified nanoparticles show no antimicrobial activity despite claims to the contrary for this assay. Results will be discussed in terms of the need for researchers without a background in microbiology to understand the mechanism of antimicrobial action before choosing an assay. Also discussed is the importance understanding the physiochemical characteristics of when interpreting results. Finally the relevance of the results in terms establishing protocols for method development for 'nanoparticle specific' antimicrobial properties will also be considered.

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A method is described for determining the oxygen content in whole blood with the membrane-covered oxygen electrode that requires less time and skill than the Van Slyke-Neill technique. A blood sample (0.05 ml) is mixed with a large volume of dilute (0.2% w/v) potassium ferricyanide solution in equilibrium with ambient air and the oxygen tension of the mixture is measured at a known temperature. The whole-blood oxygen content is obtained by subtracting the calculated O2 content of the ferricyanide solution from that of the blood-ferricyanide mixture. The method is based on the assumption that the Bunsen O2 solubility coefficient of the ferricyanide solution, with or without the added blood sample, is equal to the solubility coefficient of water. Data have been presented to validate this assumption. Whole-blood O2 contents measured simultaneously with the oxygen electrode and the Van Slyke-Neill technique were found to be in close agreement. flood-gas determination Submitted on January 11, 1965

Establishing realistic exposure scenarios is critical for cytotoxic investigation of silver (Ag) nanoparticles in the gastrointestinal tract. This study investigated the potential interaction with and effect of biofluid components, namely cholic acid, deoxycholic acid and ursodeoxycholic acid, on AgNP toxicity. Two cell lines corresponding to organs related to the biofluid components were employed. These were HepG-2 a hepatocellular carcinoma derived from liver tissue and Hep2 an epithelial cell line. Physiochemical and cytotoxic screening was performed and the ability of biofluid components to modify AgNP cytotoxicity was explored. No alteration to the physiochemical characteristics of AgNP by biofluid components was demonstrated. However, biofluid component addition resulted in alteration of AgNP toxicity. Greater ROS induction was noted in the presence of CA and DCA. UDCA demonstrated no modification of toxicity in HEpG-2 cells however significant modification was noted in Hep2 cells. It is concluded that biofluid components can modify AgNP toxicity but this is dependent on the biofluid component itself and the location where it acts. Short AbstractSilver nanoparticle (AgNP) interaction with biofluids upon entry to the body is important for accurate toxicological investigation. A number of toxicological tests were performed and demonstrated modification of AgNP toxicity by the chosen biofluid components cholic acid, deoxycholic acid and ursodeoxycholic acid. It is concluded that the influence on AgNP toxicity by biofluid components is dependent on the biofluid component itself and the location where it acts.

:The antioxidant properties of rosemary oleoresin in precooked roast beef slices were compared to those of a butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT) combination, sodium tripolyphosphate and sodium citrate, during both refrigerated and frozen storage. Their antioxidant properties were measured by means of TBARS (TBA-reactive substances) and sensory scores. Sodium tripolyphosphate was the most e †ective antioxidant during both storage periods. Rosemary oleoresin in combination with sodium tripolyphosphate proved to be e †ective during both storage periods, but in particular, during frozen storage at preventing an increase in TBARS and at improving the Ñavour preference for the roast beef slices. Sodium citrate proved to be an ine †ective antioxidant. The treatments containing salt, phosphate plus BHA/BHT and salt plus BHA/BHT had comparable antioxidative properties to the treatments containing salt, phosphate and rosemary and salt and rosemary, respectively. No overall signiÐcant correlation coefficients were obtained between the TBARS and the sensory scores.1998 SCI. ( J Sci Food Agric 77, 235È243 (1998)

Nanotechnology is a rapidly growing field with silver nanoparticles (AgNP) in particular utilized in a wide variety of consumer products. This has presented a number of concerns relating to exposure and the associated toxicity to humans and the environment. As inhalation is the most common exposure route, this study investigates the potential toxicity of AgNP to A549 alveolar epithelial carcinoma cells and the influence of a major component of lung surfactant dipalmitoylphosphatidylcholine (DPPC) on toxicity. It was illustrated that exposure to AgNP generated low levels of oxidative stress and a reduction in cell viability. While DPPC produced no significant effect on viability studies its presence resulted in increased reactive oxygen species formation. DPPC also significantly modified the inflammatory response generated by AgNP exposure. These findings suggest a possible interaction between AgNP and DPPC causing particles to become more reactive, thus increasing oxidative insult and inflammatory response within A549 cells.