At the Small Frontier
Nanotechnology is a frontier where multiple disciplines of science and engineering intersect. Consequently, its applications encompass seemingly disparate fields ranging from medicine and biotechnology to renewable energy systems and environmental protection," explains R. "Suresh" Sureshkumar, Ph.D., professor and chair, department of biomedical and chemical engineering at the L.C. Smith College of Engineering and Computer Science of Syracuse University, Syracuse, N.Y. Sureshkumar himself uses nanobiotechnology for the energy field. His work in nanoplasmonics focuses on manipulating light to promote more efficient algal growth for the purpose of making biofuels.
However, he notes, such broad opportunities are accompanied by challenges associated with facilitating safe, large-scale use of nanoparticles by preventing or minimizing their toxic reaction to living cells and their transport into natural environments. For instance, he notes, preventing nanoparticles from infiltrating barriers such as laboratory gloves, cell membranes and polymer films used in landfills is extremely important. Further, he explains, it is important to have appropriate metrics to quantify the harmful effect of exposure to nanoparticles as a function of the exposure time, particle concentration and ambient conditions.
"Developing and adopting reliable standards for the practice of nanotechnology is critical to realizing its full potential," Sureshkumar adds.
Similarly, Ahmed Busnaina, Ph.D., sees great potential for nanotechnology - and a need for standards. Busnaina is William Lincoln Smith chair and professor in the College of Electrical and Computer Engineering, and director of the Center for High-Rate Nanomanufacturing at Northeastern University in Boston, Mass. Busnaina, one of the world's foremost authorities on nanotechnology, says standards are crucial to efforts to move nanotechnology into manufacturing. "Without standards for raw materials it can be very hard to manufacture nanoscale products," he says.
In 2005, stakeholders interested in standardizing the terminology of the burgeoning nanotechnology field formed ASTM Committee E56 on Nanotechnology. Committee E56 addresses issues related to general standards and guidance materials for nanotechnology and nanomaterials, as well as the coordination of existing ASTM standards related to nanotechnology needs. The committee also fields specific requests for nanotechnology standards through ASTM's existing committee base and maintains global liaison relationships related to this subject area.
Committee E56 chairman Debra L. Kaiser, Sc.D., is chief of the Ceramics Division at the National Institute of Standards and Technology Measurement Laboratory in Gaithersburg, Md. She says the committee has become more active over the past two years and will likely publish six new standards this year. "We focus primarily on standard guides and test methods for measurement of nanoparticles rather than classification type documents," Kaiser says. A new area for E56 is the application of informatics to nanomaterials\; the committee will soon publish a specification for a standard file format for nanomaterial data that will enable better exchange of data from different laboratories.
"We have a fairly new subcommittee on nano-enabled products," Kaiser says. "This subcommittee has received considerable attention and interest from people in industry as well as from other government agencies such as the U.S. Food and Drug Administration."
According to Kaiser, ASTM International's efforts in nanotechnology have been undertaken largely in response to needs expressed by industry or government agencies. Because ASTM is based on voluntary participation, those with the need - and the technical know-how - are often the people who draft standards working within the ASTM framework.
In the case of nanotechnology, the challenge is measuring things smaller than what people are accustomed to measuring, "so it pushes the state of the art of measurement," Kaiser says. Furthermore, the materials themselves often present many challenges. "When you fabricate or purchase a nanomaterial for use in developing a standard, the material may not be homogeneous," she says. Measuring such materials often requires intricate sample preparation procedures. For instance, "you may need to disperse the nanoparticles so that you can measure individual nanoparticles using microscopy methods," she says.
A key is providing well-defined methods and guidance for conducting measurements so that the results are repeatable. The standards development process is enabled by ASTM's "wonderful infrastructure for interlaboratory studies," Kaiser says, a process in which samples from the same source are sent to multiple laboratories that each measures the sample using the same standard test method. The participating labs send their data back to ASTM, utilizing the ASTM Interlaboratory Study Program, and ASTM compiles the data from different labs, analyzes the data and reports a precision statement that indicates reproducibility of the standard test method. "Regulatory agencies are starting to indicate that they would like to see broader use of interlaboratory studies so that they can have some measure of the precision of the test method," says Kaiser.
Alan Rawle, Malvern Instruments, Westborough, Mass., who also serves on Committee E56, says his company has been in the nanotech field from its inception in the 1970s. Malvern Instruments grew out of work at the Royal Radar Establishment in the United Kingdom regarding the analysis of signal clutter and devised insights that turned out to apply to the analysis of Brownian particle motion.
Involved in the committee from its inception, Rawle says he has been impressed with the work of ASTM International and particularly the way the organization is able to deliver results rapidly. "I have also been involved with ISO [International Organization for Standardization], and they appear to have a much longer time to market," he says. "ASTM is a joy to work with\; everything is smooth and the administrative support is great."
Other ASTM International committees have long been developing standards for aspects of their industry that utilize nanotechnology. Some of ASTM International's technical committees, such as Committees B08 on Metallic and Inorganic Coatings and F04 on Medical and Surgical Materials and Devices, have for many years been developing standards for aspects of their industries that utilize nanotechnology.
ASTM Committee B08, formed in 1941, focuses on nanomaterials within its broader mission. The committee has a current membership of more than 120 industry professionals and oversees 130+ standards in total.
Christina Lomasney, founder and CEO of Modumetal, a nanotechnology company in Seattle, Wash., has been involved with B08 since 2010. Lomasney explains that traditional ASTM standards in the coatings area had tended to focus on defining the process for making a coating rather than the performance of the coating. Therefore materials created through novel processing means, even when the new materials can demonstrate superior performance, are not covered by the existing standards. "It isn't possible to cross-specify performance and process requirements, therefore nanostructed zinc coatings, for example, can't qualify under conventional zinc coating specifications because the nanotechnology products are achieved by a different process," she explains.
With that concern in mind, Lomasney says the committee is working with industry to develop test methods and quality control methods that are more open to nanomaterials.
ASTM Committee F04 is another active player in nanotechnology. Committee E56's liaison to F04, Martin Fritts, now a guest researcher at NIST, was previously associated with the Nanotechnology Characterization Laboratory, Frederick, Md., a group that is part of the National Cancer Institute at the U.S. National Institutes of Health and is focused on performing and standardizing the preclinical characterization of nanomaterials intended for cancer therapeutics and diagnostics. "What became obvious early on is that no one really knew the exact structure of a nanomaterial either at the atomic level or more generally, since manufactured samples exhibited large variations in the size and form of their component nanomaterials," he says. "We needed standard methods so we could measure with more precision and reproducibility, and we wanted to have an agreed-upon nomenclature to describe these materials consistently."
Although ISO was also starting a standards development process for nanotechnology, Fritts says he chose to work more with ASTM International because he believes the ASTM standards development process works more quickly and because ASTM includes the results of interlaboratory testing in their standards. "ASTM has a rational process emphasizing reproducibility - and it is international but has a streamlined voting procedure," he adds.
Jennifer Hall Grossman, a scientist with NCL who has participated in ASTM International interlaboratory studies, says the different relationships forged through ASTM are productive ones. Indeed, she points to the work of those within her laboratory who have contributed to ASTM committee work.
"NCL scientists ended up contributing to the creation of three protocols which eventually became ASTM standards for nanotech in biotechnology applications - a first for that field," says Grossman.
The three standards to which Grossman refers are E2526, Test Method for Evaluation of Cytotoxicity of Nanoparticulate Materials in Porcine Kidney Cells and Human Hepatocarcinoma Cells, which evaluates the toxicity of nanomaterials by examining their effects on kidney and cancerous liver cells\; E2524, Test Method for Analysis of Hemolytic Properties of Nanoparticles, which assesses the effect of nanoparticulate materials on the integrity of red blood cells (all intravenously administered pharmaceuticals must be examined in regard to their hemolytic potential)\; and E2525, Test Method for Evaluation of the Effect of Nanoparticulate Materials on the Formation of Mouse Granulocyte-Macrophage Colonies, which evaluates nanoparticle stimulation or inhibition of certain bone marrow cells (macrophages). The inhibition of these cells is a common side effect of anti-cancer drugs.
The impetus for the development of these standards is at the heart of why standards are so important. According to NCL, the question of whether nanomaterials are more or less toxic than their macro-scale counterparts has been a subject of controversy. The results of scientific studies in the area have been inconsistent, in part due to the variety of assays used. Coming up with a definitive answer requires the use of standard methods, such as those described by E2524, E2525 and E2526.
Consistency then becomes a foundation for advancing both science and technology. Notes E56 chairman Kaiser, "It is like having a recipe - the standard helps guarantee that the results from lab to lab and organization to organization are consistent."Alan R. Earls is a writer and author who covers business and technology topics for newspapers, magazines and websites. He is based near Boston, Mass.
Nanotechnology is the science and technology of working with material in which physical features are to some extent engineered or manipulated on an atomic or molecular scale. In general, that means dimensions that range from 1 to 100 nanometers (a nanometer is one billionth of a meter). National governments and private industry have invested heavily in this area in the hopes that new materials and processes may result in fields as diverse as energy and biotech.