A substance might potentially be harmful or even toxic for a biological system, provided that the quantity or the concentration (the "dose") is high enough. This principle forms the basis for health standards which determine the maximum permissible concentration of contaminations, for example in food, water or in the environment. Dose calculation is of high relevance for risk assessment as well as for regulations, for instance to determine the maximum allowable concentration of chemicals and particles or to determine other limits which do not cause health problems. In the case of nanomaterials, especially for nanoparticles there is to date, no limit regulation or any other regulation referring to dose, because the definition of dose for nanoparticles does not exist. The wherefores will be explained in this dossier.
Several studies in the literature have highlighted that as nanomaterials "age" they can undergo oxidation; sintering (coalescence); surface ligand displacement; smaller nanoparticle formation; and surface carbonate formation. Nevertheless, no studies are available on how these changes affect the physicochemical properties of the nanomaterials. The aging of nanomaterials is expected to be rapid even under ambient environmental conditions. With the consequence that pristine, as synthesized materials - which are commonly used in nanotechnology-relevant environmental health and safety (EHS) studies - are never really encountered under natural environmental conditions. Which means that researchers who investigate the applications and implications of nanomaterials need to have a clear understanding of the aging process of these materials and need to take its effects into consideration.
A group of experts from the chemical industry and various research laboratories in Germany have published a report on the current status of risk research on nanotechnology materials and applications. The report - 10 Years of Research: Risk Assessment, Human and Environmental Toxicology of Nanomaterials - provides an overview of the current state of risk assessment and toxicological research into nanomaterials. It also lists and summarizes the national and European projects on toxicology on various nanomaterials. In their report, the working group "Responsible Production and Use of Nanomaterials" has drawn up a list of topics and priorities which need to be addressed; activities and projects which have already been carried out; are currently on-going; or are still at the planning stage. The main focus of our considerations is on Germany, with a wider outlook on papers and results at European level.
Following up on our recent Nanowerk Spotlight on nanofoods, new research shows that consumers could be exposed to nanoparticles in food by a much larger degree than has been expected so far. For a modern consumer it is hard to avoid titanium dioxide (TiO2) - a widely used additive in food, personal care and other household products. Approximately 7 million tons of bulk TiO2 are produced annually and used as white pigment in order to provide whiteness and opacity to foods and other products. Many applications of titanium dioxide would benefit from smaller primary particle sizes, and we can expect the percentage of TiO2 that is produced in or near the nano range to increase.
In a project funded by the Danish Environemntal Protection Agency, researchers have initiated the development of a screening tool called NanoRiskCat for the evaluation of exposure and hazard of nanomaterials contained in products for professional and private use. The project's aim was to identify, categorize and rank the possible exposure and hazards associated with a nanomaterial in a product. NanoRiskCat is using a stepwise approach based on existing data on the conventional form of the chemical as well as the data that may exist on the nanoform. However, the tool still needs to be further validated and tested on a series of various nano products in order to adjust and optimize the concept and thereby to achieve a screening tool as informative and practical as possible.
Early detection of food borne pathogenic bacteria is critical to prevent disease outbreaks and preserve public health. This has led to urgent demands to develop highly efficient strategies for isolating and detecting this microorganism in connection to food safety, medical diagnostics, water quality, and counter-terrorism. Conventional techniques to detect E. coli and other pathogenic bacteria are time-consuming, labor-intensive, and inadequate as they lack the ability to detect bacteria in real time. Thus, there is an urgent need for alternative platforms for the rapid, sensitive, reliable and simple isolation and detection pathogens. Taking a novel approach to isolating pathogenic bacteria from complex clinical, environmental and food samples, researchers have developed a nanomotor strategy that involves the movement of lectin-functionalized microengines. Receptor-functionalized nanoswimmers offer direct and rapid target isolation from raw biological samples without preparatory and washing steps.
Naturally occurring nanomaterials can be found everywhere in nature and only with recent advances in instrumentation and metrology equipment are researchers beginning to locate, isolate, characterize and classify the vast range of their structural and chemical varieties. Scientists are beginning to recognize that all sources of nanomaterials are important in evaluating the possible impact of nanoscale materials on human health and the environment; however, perhaps the greatest benefit to studying these materials will be in their ability to inform researchers about the manner in which nano-sized materials have been a part of our environment from the beginning.
Colloidal silver is not a health elixir and should not be taken orally. Still, dubious online resources that sell silver dispersions or explain how to synthesize colloidal silver for nutritional purposes keep propagating mystic health effects of nano-silver. Whoever considers to "treat" themselves by taking colloidal silver certainly don't know what they want to treat themselves for. They should be aware that drinking an antimicrobial agent at any effectual dosage must inevitably cause harm to innumerable bacteria that are vital to our organism - especially in the alimentary canal. Drinking colloidal silver will either be noneffective or harmful. It is not medicine.