Carbon nanotubes (CNTs) have shown promise as an important new class of multifunctional building blocks and innovative tools in a large variety of nanotechnology applications, ranging from nanocomposite materials through nanoelectronics to biomedical devices (e.g. gene and drug carriers). The recent rapid development in nanotechnology has renewed the pressing demand for large-scale production of CNTs for potential applications in commercial products. The number of industrial-scale facilities for the increasingly low-cost production of multi-walled carbon nanotubes (MWCNTs) continues to grow, and with that the professional and public exposure to MWCNTs is expected to increase significantly in the coming years. Owing to their unusual one-dimensional hollow nanostructure and unique physicochemical properties, CNTs are particularly useful as novel drug delivery tools and imaging agents. However, such biomedical, and many other related, applications will not be realized if there is no proper assessment of the potential hazards of CNTs to humans and other biological systems. This situation prompted a group of researchers to carry out the first genotoxicity study of nanomaterials. Although the health effects of nanomaterials have attracted considerable attention, the scientific community has thus far focused primarily on the studies of nanomaterials toxicity at the cellular level. Very little is known about the toxicity at the molecular level, or genotoxicity, of nanomaterials in mammalian cells. Researchers at the University of Dayton have assessed the DNA damage response to MWCNTs in mouse embryonic stem cells (ES). This new work emphasizes the importance of careful scrutiny of the genotoxicity of nanomaterials.
Governments always struggle when faced with regulating highly complex subject matters such as nanotechnologies. Primarily concerned with managing the potential risks to the environment, human health and the safety of workers (EHS), regulators often feel overwhelmed by the complexity and novelty of new technologies, stymied by a lack of data, and confused by conflicting research findings and advice from various interest groups. In the meantime, against a backdrop of a legal environment that ranges from gaping holes to regulatory vacuum, research organizations and early-adopting industry players push ahead with the new technology. Not being able to create any breathing room for lengthy political and legal considerations, the last 15-20 years have seen several governments adopting voluntary environmental programs (VEPs), arguing that this is the only viable proportional option for the time being. It is estimated that there are some 300 VEPs in the European Union and over 200 in the United States, dealing with matters such as climate change, energy, waste, water, toxic materials, agriculture, manufacturing, mining, forestry, hotels, hospitals, and financial institutions. If these voluntary programs work is subject to debate - some apparently do, some less so. In the case of manufactured nanomaterials, the risk properties remain largely unknown and it is unclear what exactly should be regulated. For the VEPs that are in place for nanomaterials, governments are urging companies to submit health and safety information on the nanomaterials they produce or commercialize. In order to investigate whether voluntary government programs will be sufficient to ensure the safety of manufactured nanomaterials, researchers have analyzed a sampling of voluntary programs in the fields of environmental health and safety in the United States over the past 20 years, with a view towards their applicability in the case of manufactured nanomaterials
The benefits of new technologies, whether they are new medical treatments, an innovative approach to farming or new ways of generating energy, almost always come with some new risks as well. In the emerging stages of a new technology, experts and the public generally differ in their perceptions of risk. While this might be due to social and demographic factors, it is generally assumed by scientists who conduct risk research that experts' risk assessments are based more strongly on actual or perceived knowledge about a technology than lay people's risk assessments. Nevertheless, whether the risks are real or not, the public perception of an emerging technology will have a major influence on the acceptance of this technology and its commercial success. If the public perception turns negative, potentially beneficial technologies will be severely constrained as is the case for instance with gene technology. It is not surprising that a new study found that, in general, nanoscientists are more optimistic than the public about the potential benefits of nanotechnology. What is surprising though, is that, for some issues related to the environmental and long-term health impacts of nanotechnology, nanoscientists seem to be significantly more concerned than the public.
Earlier this year, the Science Policy Council of the U.S. Environmental Protection EPA (EPA) issued the final version of its Nanotechnology White Paper. The purpose of this White Paper is to inform EPA management of the science issues and needs associated with nanotechnology, to support related EPA program office needs, and to communicate these nanotechnology science issues to stakeholders and the public. While this has been the publicly most visible EPA activity with regard to nanotechnology, it is less widely known that the EPA, since 2002, has been spending more than $25 million through its Science to Achieve Results (STAR) grants program for 86 projects on research into the environmental aspects of nanotechnology. The projects are broadly grouped into two main categories: 1) nanotechnology applications - examining beneficial uses - where the areas of research include green manufacturing, contamination remediation, sensors for environmental pollutants, and waste treatment; and 2) nanotechnology implications - examining the potentially adverse health effects to humans and the environment - where research is grouped into five categories: aerosol, exposure assessment, fate and transport, life-cycle analysis, and toxicity.
Our title today poses a loaded question. The cosmetics industry of course would argue that their products are already safe, whether they use nanoparticulate ingredients or not. On the other hand, there are research reports that show that nanoparticles could cause DNA damage and could accumulate in organs (with unknown consequences). It has not conclusively been proven, or disproven, that nanoparticles in cosmetics applied to the (healthy) skin are able to penetrate the skin and get into the body. Sunscreens are a good example for the pro and contra discussion about nanoparticles in cosmetics. Most people use sunscreen for two reasons: to avoid getting sunburn and to avoid getting skin cancer. If applied frequently and thoroughly, sunscreens do prevent sunburn. However, no one has ever determined that sunscreens actually prevent skin cancer. Another, mostly aesthetic, limitation with sunscreens is that they don't rub into the skin very easily. You rub, and rub, and rub, but still your skin has that pasty, white appearance. That's due to the two most common active ingredients in sunscreens - zinc oxide (ZnO) and titanium dioxide (TiO2). These inorganic materials are used in sunscreen in order to reflect UV radiation and reduce the amount of organic materials necessary to achieve a specific SPF (sun protection factor) value, but the drawback is they leave that unsightly white film. To resolve this problem, manufacturers have started using nanoparticles in place of the bulk forms of zinc oxide and titanium dioxide because the smaller particle size reduces the visibility of the cream. This could potentially mean solving one problem by creating another because TiO2 nanoparticles - a major component of photovoltaic cells - emit photoelectrons when exposed to UV light. These electrons, in turn, induce the formation of peroxides, free radicals and other reactive oxygen species (ROS) which interact with lipids and DNA, causing damage which may lead to a host of medical problems. Researchers have now found clear evidence that titanium dioxide nanoparticles catalyze DNA damage. Fortunately, they also came up with a solution - by coating them - that would allow these nanoparticles to be used with less risk in cosmetics.
What do humans have in common with the pinky-sized tropical zebrafish that zip around in many hobbyists' home aquariums? Well, surprising as it may be, quite a lot actually. Zebrafish share the same set of genes as humans and have similar drug target sites for treating human diseases. For this reason, scientists, when turning to a model-organism to help answer genetic questions that cannot be easily addressed in humans, often chose the zebrafish (Danio rerio) - and save a few mice in the process. Zebrafish are small, easy to maintain, and well-suited for whole animal studies. Furthermore, its early embryonic development is completed rapidly within five days with well-characterized developmental stages. The embryos are transparent and develop outside of their mothers, permitting direct visual detection of pathological embryonic death, mal-development phenotypes, and study of real-time transport and effects of nanoparticles in vivo. Therefore, zebrafish embryos offer a unique opportunity to investigate the effects of nanoparticles upon intact cellular systems that communicate with each other to orchestrate the events of early embryonic development. In a new study, researchers explore the potential of nanoparticles as in vivo imaging and therapeutic agents and develop an effective and inexpensive in vivo zebrafish model system to screen biocompatibility and toxicity of nanomaterials. Such real-time studies of the transport and biocompatibility of single nanoparticles in the early development of embryos will provide new insights into molecular transport mechanisms and the structure of developing embryos at nanometer spatial resolution in vivo, as well as assessing the biocompatibility of single-nanoparticle probes in vivo.
In an earlier Spotlight we reported on NIOSH's Nanotechnology Research Center (NTRC) and its efforts concerning the occupational safety and health perspectives of engineered nanomaterials (Nanotechnology in the workplace). Today, we are looking at the specific steps undertaken by companies active in the field. "We were receiving a steady stream of questions from industry and academia regarding what we knew about the hazards of nanomaterials," Charles L. Geraci, Branch Chief at the National Institute of Occupational Safety and Health (NIOSH) and Co-Coordinator of the NIOSH Nanotechnology Field Team, tells Nanowerk. "People were coming to NIOSH for recommendations; we knew we needed to have a better understanding of the nature of workplace exposure during research, production and use." But, in a new and relatively little studied area of industry, where does one find these answers? NIOSH already had a strong research program to address questions in the lab, says Geraci, but field data was needed to have a complete picture. "In our minds, the best way to achieve this was to do what NIOSH does best: get in the field and gather data through observation and measurement." In 2006, the concept of a field team dedicated to this effort was developed.
New technology, whether it is a novel cancer treatment or an innovative approach to making a new material, almost always comes with risk. Nanotechnologies are no different. Certain nano-fabrication techniques employ toxic chemicals, the production of carbon nanotubes results in dangerous byproducts, and the big question as to what degree certain engineered nanoparticles could be harmful to humans and the environment has not been answered yet. The potentially adverse health effects of fine and ultrafine particles have been studied for decades. However, at the core of the nanotoxicological debate is the fact that nanoparticles are not just a smaller version of certain particles, but they are very different from their everyday counterparts with regard to their physical properties and catalytic activities. Thus their adverse effects cannot simply be derived from the known toxicity of the macro-sized material. One useful contribution to moving the nanotoxicology discussion further along came from the 1st Nobel Forum Mini-Symposium on Nanotoxicology that was held in Stockholm, Sweden. The event's program was devoted to the topic of definitions and standardization in nanotoxicological research, as well as nano-specific risk assessment and regulatory/legislative issues. A group of international experts presented examples of recent and ongoing studies of carbon-based nanomaterials, including single-walled carbon nanotubes, using a wide range of in vitro and in vivo model systems. This Spotlight will provide you with some highlights and conclusions from this exciting meeting.