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.
Metal nanomaterials are often synthesized using the toxic reagent formaldehyde at concentrations thousands of times higher than necessary. Many of these same nanomaterials are being investigated for use in cancer treatment - however, there is a risk that they could do more harm than good. The large excess of formaldehyde that is used originates from methods developed 100 years ago. Because these methods work well, they have stood the test of time. By better understanding the role that formaldehyde plays in nanomaterial synthesis it will become possible to reduce or eliminate this toxic reagent. By eliminating formaldehyde it will become safer to prepare these nanomaterials and safer to use them in cancer treatment.
One of the key issues in the young field of nanotoxicology is the lack of standards and definitions. Although there have been some efforts, there still is no coherent international approach to determining if and what risks are posed by what kind of nanotechnology materials. At the core of the problem are the serious challenges that are created when comparing test results and drawing conclusions without adequate standardization and nanomaterial characterization. Exemplifying this set of problems further, a new study shows that even the most basic set of data, the nanomaterial characterization information provided by the manufacturer, can't be relied on - something which shouldn't come as a complete surprise given the existing problems with characterization data.
Silver nanoparticles can now be found in all kinds of products, from socks to food containers to coatings for medical devices. Valued for its infection-fighting, antimicrobial properties, silver, in its modern incarnation as silver nanoparticles, has become the promising antimicrobial material in a variety of applications because the nanoparticles can damage bacterial cells. Due to their plasmonic properties and easy surface chemistry silver nanoparticles are also beginning to attract interest among nanomedicine researchers. However, the surface chemistry of nanoparticles that governs their interactions with other constituents in their environment has critical importance. Therefore, chemically altering the surface properties of nanoparticles with polymers, biological ligands and macromolecules is actively being explored.
Some scientists believe that, with the increased mass production of engineered nanoparticles like carbon nanotubes, there is a realistic chance for these particles to interact with water, soil and air, and subsequently enter the food chain. However, understanding the behavior and impacts of nanomaterials in the environment and in human health is a daunting task. Nevertheless, a general understanding about nanotoxicity is slowly emerging as the body of research on cytotoxicity, genotoxicity, and ecotoxicity of nanomaterials grows. In our Spotlight today we take a look at new biophysical research - a parallel study of carbon-nanoparticle uptake by plant and mammalian cells - that contributes to the general picture of the fundamental behaviors of nanoparticles in both biological and ecological systems.
In 2008, the Joint Research Centre, Institute for Health and Consumer Protection of the European Commission funded the project Engineered Nanoparticles: Review of Health and Environmental Safety (ENRHES). Last month, the ENRHES project released its final report. The overall aim of the ENRHES project was to perform a comprehensive and critical scientific review of the health and environmental safety of four classes of nanomaterials: fullerenes, carbon nanotubes, metals and metal oxides. The review considers sources, pathways of exposure, the health and environmental outcomes of concern, illustrating the state-of-the-art and identifying knowledge gaps in the field, in order to coalesce the evidence which has emerged to date and inform regulators of the potential risks of engineered nanoparticles in these specific classes.