Although the literature grows on the use of science to inform decisions on the environmental, health and safety implications of nanotechnology, little has been published by those who make such decisions. In a recent commentary in Nature Nanotechnology, officials of the US Environmental Protection Agency (EPA), the European Commission and the Organisation for Economic Co-operation and Development (OECD), discuss the types of decision facing government regulators, the new considerations nanotechnology brings to decision-making, the role of science in informing decisions, how regulators cooperate internationally on policy issues, and the challenges that lie ahead. The authors provide an overview of key reports and regulations and then discuss the complexity of issues with regard to addressing nanomaterials within the context of existing regulations and the need to weigh nanomaterial risk and benefits.
The use of minute particles as drug carriers for targeted therapy has been studied and discussed for more than 20 years. A selective accumulation of active substances in target tissues has been demonstrated for certain so-called nanocarrier systems that are administered bound to pharmaceutical drugs. Great expectations are placed on nanocarrier systems that can overcome natural barriers such as the blood-brain barrier (BBB) and transport the medication directly to the desired tissue and thus heal neurological diseases that were formerly incurable. The BBB represents the border between the circulating blood and the fluid in the central nervous system. It functions to protect the sensitive nerve cells from foreign substances and infections from the blood. Whether nanoparticles enter the central nervous system unintentionally and induce health problems is also being debated.
In a new research field that could be called 'experimental nanotoxicology', scientists have now, for the first time, demonstrated that biological effects of manufactured nanoparticles can be predicted using their chemical, physical, and geometrical properties. The results successfully demonstrate the high potential of cheminformatics approaches for improving the experimental design and prioritizing the biological testing of novel manufactured nanoparticles. The team modeled their approach after a process used in drug design and chemical synthesis, where the chemical structure of a new compound is quantitatively correlated with a well defined process, such as biological activity or chemical reactivity. Such a Quantitative Structure Activity Relationship (QSAR) can then be utilized to help guide chemical synthesis and drug design. They termed their approach quantitative nanostructure-activity relationship (QNAR) modeling.
Understanding the behavior and impacts of nanomaterials in the environment and in human health is a daunting task. Today, we don't even know what the impact of most chemicals is, and that includes products we have been using for many years. Nevertheless, a general understanding about nanotoxicity is slowly emerging as the body of research on cytotoxicity, genotoxicity, and ecotoxicity of nanomaterials grows. Many of the published toxicity studies have limited relevance, due, in large part, to study design limitations, including inadequate justification for dose selection or route of exposure criteria. A recently published article addresses myths and misconceptions regarding nanotoxicology.
Silver nanoparticles are one of the most extensively used type of nanoparticles in consumer products due to the unique antibacterial activity of silver. There have been raising environmental concerns over their adverse ecological effects, along with ionic silver potentially released from the particles. To predict the environmental impact of engineered silver nanoparticles, their characterization from environmental matrices should be pursued, yet no field-scale studies are available to date. A new research report was motivated by the fact that silver nanoparticles in consumer products are likely being released during and/or after the product's lifetime. The silver nanoparticles will likely get into wastewater streams and subsequently enter wastewater treatment plants. During wastewater treatment processes, silver nanoparticles may be incorporated into the sewage sludge matrix and concentrated over time.
Silver had already been recognized in ancient Greece and Rome for its infection-fighting properties but in modern times pharmaceutical companies made more money developing antibiotics. However, thanks to emerging nanotechnology applications, silver has made a comeback in the form of antimicrobial nanoparticle coatings for textiles, surgical instruments, lab equipment, floors or wall paints. The flip side of silver's desired toxicity towards microbes is that it might have toxic effects for humans as well and this has raised debate about the safety of nanosilver products. Although scientists have worked to reduce the toxicity of antimicrobial nanosilver in products, concerns remain. Not helping to put these concerns to rest is a new report from a group of researchers in Germany that shows that toxicity of silver nanoparticles increases during storage because of slow dissolution under release of silver ions.
Tailing after emerging nanotechnology applications in biomedical and electronic industries, the construction industry recently started seeking out a way to advance conventional construction materials using a variety of manufactured nanomaterials. The use of nanotechnology materials and applications in the construction industry should be considered not only for enhancing material properties and functions but also in the context of energy conservation. This is a particularly important prospect since a high percentage of all energy used (e.g., 41% in the United States) is consumed by commercial buildings and residential houses by applications such as heating, lighting, and air conditioning. A recent review by scientists at Rice University has looked at the benefits of using nanomaterials in construction materials but also highlights the potentially harmful aspects of releasing nanomaterials into the environment.
Carbon nanotubes' interesting structural, chemical, electrical, and optical properties are explored by numerous nanomedicine research groups around the world with the goal of drastically improving performance and efficacy of biological detection, imaging, and therapy applications. In many of these envisaged applications, CNTs would be deliberately injected or implanted in the body, for instance as intercellular molecular delivery vehicles. One of the issues researchers have been exploring is how - once the primary role of CNTs in a therapeutic application is fulfilled - they can promote the rapid removal of CNTs from the body, or the dispersal of aggregated clusters to sub-micron size in order to mitigate the harmful effects. Researchers in India have now demonstrated a novel, optical tweezers based approach to scavenge CNTs from biological fluids such as blood.