may result in oxidative stress, inflammation, and consequent damage to proteins, membranes and dna. for example, the application of nanoparticle metal oxide with magnetic fields that modulate ros leading to enhanced tumor growth. cytotoxicity a primary marker for the damaging effects of nps has been cell viability as determined by state and exposed surface area of the cell membrane. cells exposed to metallic nps have, in the case of copper oxide, had up to 60% of their cells rendered unviable. when diluted, the positively charged metal ions often experience an electrostatic attraction to the cell membrane of nearby cells, covering the membrane and preventing it from permeating the necessary fuels and wastes. with less exposed membrane for transportation and communication, the cells are often rendered inactive. nps have been found to induce apoptosis in certain cells primarily due to the mitochondrial damage and oxidative stress brought on by the foreign nps electrostatic reactions. genotoxicity metal and metal oxide nps such as silver, zinc, copper oxide, uraninite, and cobalt oxide have also been found to cause dna damage. the damage done to the dna will often result in mutated cells and colonies as found with the hprt gene test. methods and standards characterization of a nanomaterial's physical and chemical properties is important for ensuring the reproducibility of toxicology studies, and is also vital for studying how the properties of nanomaterials determine their biological effects. the properties of a nanomaterial such as size distribution and agglomeration state can change as a material is prepared and used in toxicology studies, making it important to measure them at different points in the experiment. with comparison to more conventional toxicology studies, in nanotoxicology, characterisation of the potential contaminants is challenging. the biological systems are themselves still not completely known at this scale. visualisation methods such as electron microscopy (sem and tem) and atomic force microscopy (afm) analysis allow visualisation of the nano world. further nanotoxicology studies will require precise characterisation of the specificities of a given nano-element: size, chemical composition, detailed shape, level of aggregation, combination with other vectors, etc. above all, these properties would have to be determined not only on the nanocomponent before its introduction in the living environment but also in the (mostly aqueous) biological environment. there is a need for new methodologies to quickly assess the presence and reactivity of nanoparticles in commercial, environmental, and biological samples since current detection techniques require expensive and complex analytical instrumentation. policy and regulatory aspects toxicology studies of nanomaterials are a key input into determining occupational exposure limits. the royal society identifies the potential for nanoparticles to penetrate the skin, and recommends that the use of nanoparticles in cosmetics be conditional upon a favorable assessment by the relevant european commission safety advisory committee. the woodrow wilson centre's project on emerging technologies conclude that there is insufficient funding for human health and safety research, and as a result there is currently limited understanding of the human health and safety risks associated with nanotechnology. while the us national nanotechnology initiative reports that around four percent (about $40 million) is dedicated to risk related research and development, the woodrow wilson centre estimate that only around $11 million is actually directed towards risk related research. they argued in 2007 that it would be necessary to increase funding to a minimum of $50 million in the following two years so as to fill the gaps in knowledge in these areas. the potential for workplace exposure was highlighted by the 2004 royal society report which recommended a review of existing regulations to assess and control workplace exposure to nanoparticles and nanotubes. the report expressed particular concern for the inhalation of large quantities of nanoparticles by workers involved in the manufacturing process. stakeholders concerned by the lack of a regulatory framework to assess and control risks associated with the release of nanoparticles and nanotubes have drawn parallels with bovine spongiform encephalopathy (‘mad cow's disease'), thalidomide, genetically modified food, nuclear energy, reproductive technologies, biotechnology, and asbestosis. in light of such concerns, the canadian-based etc group have called for a moratorium on nano-related research until comprehensive regulatory frameworks are developed that will ensure workplace safety.