Nano Dictionary

It's basically been a free-for-all in the world of nanotech terminology. Quantum dots, nanoshells, nanopeapods--nanoscientists have been inspired by everything from Polish dumplings to Inuit landmarks when naming new nanomaterials. But without any systematic terminology or nomenclature, these myriad descriptors, along with vague terms such as nanoparticle, are quickly becoming a big headache for regulators, patent lawyers, and journal editors.

Last month at the ACS national meeting in San Diego, Vicki Colvin, director of the Center for Biological & Environmental Nanotechnology and chemistry professor at Rice University, told a standing-room-only crowd about a project she's spearheaded to create a dictionary for the nanoscale. Colvin hopes that by developing standard terminology for nanomaterials, she and her colleagues will be able to create a common language that helps scientists and nonscientists alike.

Thomas E. Mallouk, a chemistry professor at Pennsylvania State University, told C&EN that the project is very important in the development of nanotechnology. "It is a good idea to have a standard nomenclature for nanomaterials" he said. "Otherwise, many different nomenclatures will spontaneously arise and cause confusion down the road."

Mallouk, who is also an associate editor of the Journal of the American Chemical Society, added, "From the point of view of a journal editor, or, more importantly, a journal reader, a good system of nomenclature helps put new discoveries in the context of previous ones and helps knit together the science of the field."

To date, fullerenes are the only type of nanoparticle that have been named in any systematic manner, according to Colvin. Even though TiO₂ nanoparticles and carbon nanotubes are already showing up in commercial products, these and other nanoparticles are currently classified under federal regulations that don't differentiate between bulk chemicals and their nanoparticulate forms. "Saying what the chemical composition alone is sort of misses the boat," Colvin explained. " the nanomaterial was the same as the bulk, we wouldn't be investing a billion dollars each year trying to build the nanotechnology industry."

Colvin is developing her "dictionary for the nanoscale" under the auspices of ASTM International, within the standards development organization's technical committee on nanotechnology. Colvin is chair of the committee, which is expected to get the official nod from ASTM International's board of directors this week.

Although the committee plans to tackle other nanotechnology standards, like occupational health and product stewardship, ASTM sees the nano terminology project as the foundation for those efforts. Consequently, the committee leaders have laid out an ambitious timeline. Pat Picariello, the committee's staff manager, said they plan to have a first draft of the proposed terminology completed and circulating among members of the committee by the end of April, and they expect a final draft will be ready by July.

Colvin is concentrating on naming "bottom-up" nanomaterials like nanotubes and quantum dots, rather than "top-down" structures made using lithography. She envisions a standard nomenclature that would specify size, composition, surface coatings, and a number of other parameters.

Kristen M. Kulinowski, Colvin's colleague at Rice, has been working closely with her on the project. Kulinowski told C&EN that covering the vast range of nanomaterials is going to be one of the project's biggest challenges. "It is a pretty broad undertaking, and there may not be a single set of rules that work for every type of nanomaterial," she said.

Simply establishing general terminology for nanotech has turned out to be surprisingly controversial, Kulinowski noted. One of the most contentious issues: Just what qualifies as nano? The term "nano" has been applied to everything from particles just a few nanometers across to larger objects that measure a few hundred nanometers in size. No company that has touted itself as a nanotech enterprise wants to lose the cachet of that descriptor because it doesn't fit some standard definition, Kulinowski explained.

CREATING a naming system that appeals to every type of scientist and engineer working in nanotech--each with their own disciplinary vernacular--also promises to be a challenge. Committee leaders have been trying to recruit scientists from a broad range of disciplines. "We welcome participation from any group that thinks it has a stake in the final product," Kulinowski said.

Colvin encouraged everyone at her presentation, at a Division of Industrial & Engineering Chemistry session, to become a member of the ASTM committee on nanotechnology. Creating the "dictionary" is an iterative process that will take place over the Internet. Members get to weigh in on the draft documents, and, in an unusual move for the organization, ASTM will make the final publication available for free on the Web. Membership is open to anyone, Colvin said. There's no cost for students to join. For everyone else, there's an annual fee of $75.

The ASTM project isn't the only nano naming venture that's under way. On April 1, the Standardization Administration of China's first national standards for nanomaterials, which includes a glossary, went into effect. And the British Standards Institution has developed a vocabulary for nanomaterials that will be published in May.

The organization most chemists associate with nomenclature, the International Union of Pure & Applied Chemistry, currently has no active committee working on a similar project, although IUPAC officials say that doesn't mean there isn't a nascent project in the works.

Even when the nanoscale dictionary is published, Kulinowski acknowledged, it will still face another major hurdle: "getting the technical community to adopt these rules and use them in their publications."