https://venturebeat.com/wp-content/uploads/2008/04/hussain_et_al_06-17-2005.pdf

In vitro toxicity of nanoparticles in BRL 3A rat liver cells

The rapid advancement of nanotechnology has created a vast array of engineered nanomaterials (ENMs) which have unique physical (size, shape, crystallinity, surface charge) and chemical (surface coating, elemental composition and solubility) attributes. These physicochemical properties of ENMs can produce chemical conditions to induce a pro-oxidant environment in the cells, causing an imbalanced cellular energy system dependent on redox potential and thereby leading to adverse biological consequences, ranging from the initiation of inflammatory pathways through to cell death. The present study was designed to evaluate size-dependent cellular interactions of known biologically active silver nanoparticles (NPs, Ag-15nm, Ag-30nm, and Ag-55nm). Alveolar macrophages provide the first defense and were studied for their potential role in initiating oxidative stress. Cell exposure produced morphologically abnormal sizes and adherence characteristics with significant NP uptake at high doses after 24 h. Toxicity eva...

Unique cellular interaction of silver nanoparticles: size-dependent generation of reactive oxygen species.

http://molbiol.ru/forums/index.php?act=Attach&type=post&id=75938

Fluorescence probes used for detection of reactive oxygen species

The intrinsic slow growth of nitrifying bacteria and their high sensitivity to environmental perturbations often result in cell growth inhibition by toxicants. Nanoparticles are of great concern to the environment because of their small size and high catalytic properties. This work sought to determine size-dependent inhibition by Ag nanoparticles and evaluate the relationship between the inhibition and reactive oxygen species (ROS). Nanoparticles with an average size range of 9−21 nm were synthesized by varying the molar ratios of BH4− /Ag+in the solution. The resulting ROS generation was quantified in the presence and absence of the bacteria while the degree of inhibition was inferred from specific oxygen uptake rate measurements, determined by extant respirometry. By examining the correlation between nanoparticle size distribution, photocatalytic ROS generation, intracellular ROS accumulation, and nitrification inhibition, we observed that inhibition to nitrifying organisms correlated with the fraction ...

Size dependent and reactive oxygen species related nanosilver toxicity to nitrifying bacteria.

A cellular antioxidant activity (CAA) assay for quantifying the antioxidant activity of phytochemicals, food extracts, and dietary supplements has been developed Dichlorofluorescin is a probe that is trapped within cells and is easily oxidized to fluorescent dichlorofluorescein (DCF) The method measures the ability of compounds to prevent the formation of DCF by 2,2′-azobis(2-amidinopropane) dihydrochloride (ABAP)-generated peroxyl radicals in human hepatocarcinoma HepG2 cells The decrease in cellular fluorescence when compared to the control cells indicates the antioxidant capacity of the compounds The antioxidant activities of selected phytochemicals and fruit extracts were evaluated using the CAA assay, and the results were expressed in micromoles of quercetin equivalents per 100 µmol of phytochemical or micromoles of quercetin equivalents per 100 g of fresh fruit Quercetin had the highest CAA value, followed by kaempferol, epigallocatechin gallate (EGCG), myricetin, and luteolin among the pure co

Hong Wang

Papers

Quantifying cellular oxidative stress by dichlorofluorescein assay using microplate reader.