Greener Nanotech 2010: Navigating EHS for nanomaterials

by Karey Holland, Techcet Group

June 21, 2010 – The Greener Nanotech 2010 conference (June 16-18, U. of Oregon, Portland, OR) focused on both the importance of verifying that any nanomaterials products are safe for the environment and health, as well as importance of continuing to move beneficial side of nanomaterials forward. Oregon has been involved in green chemistry initiatives for over 15 years, and thus is applying these basic principles to drive for green nanotech. In the last 10 years, nanotechnologies have matured from initial "dot-com" like exuberance, where concept was enough to start a business, to a more mature development phase with significant focus on reproducible manufacturing, quality control, material stability, and environmental/health/safety (EHS).Click to Enlarge

What follows are overview key messages and information from the conference; presentations are available to anyone interested (please feel free to contact me or the authors).

Robert "Skip" Rung, president and executive director of ONAMI (Oregon Nanoscience and Microtechnologies Institute), gave an excellent presentation on the benefits of nanotechnologies to the Oregon and US economies. While anything 1-100nm in at least one dimension is lumped into the "nanotechnologies industry," he reminded that it is more relevant to consider each nanomaterial within its application industry — e.g., cosmetic, biomolecular, biomedical, semiconductor, micromachine, solar, battery, military, water purification, and most high-tech industries. (For example, 75% of all leading-edge high-tech and biomedical products include nanomaterials.) Nanomaterials can allow us to reduce the amount of materials required (read: cost), and have access to interactions not available to larger particles. In 2007, the US invested $1.8B in nanotechnologies, and $13.7B was invested worldwide. Russia has funded the Russian Corporation for Nanotechnology to the tune of $5B, with the majority of this funding being used to buy existing nanotech companies. Oregon itself has a large number of companies involved in nanomaterials: Intel, HP, Life Technologies (Invitrogen) and solar companies Solexant , REC, SolarWorld, Spectrawatt, etc. He reaffirmed that while Oregon benefits from the economic and business opportunities afforded by nanotechnologies, it is also committed to doing this without harming the environment or health.

While there is much excitement about the numerous potential improved products that use nanomaterials, there is a growing concern about the nanotech risks: airborne nanoparticles could affect the cells in our lungs, production of materials can product hazardous waste, etc. Correct choices must be made while in the materials development phase, but an impediment to development is the lack of appropriate government regulation of nanomaterial — which instead of hastening nanomaterial development has instead hampered development. Jim Hutchison, conference chairman and U of OR professor of chemistry, and member of the Safer Nanomaterials and Nanomanufacturing Initiative, reviewed 15 principles of green technology and how they apply to nanotechnology. Key to greener nanotech is reduction/elimination of hazardous materials in all aspects of the nanomaterials, from the starting materials, through the fabrication and application, to disposal.

Other speakers echoed these commitments to develop nanotechnology with low risk to ESH as a starting goal. Silver nanoparticles are known to be antimicrobial agents — e.g., Dune Sciences’ LinkedON silver nanoparticle product that is adhered to socks and other fabrics. Ag disrupts cell membranes and prevents bacterial reproduction. Ag is now being regulated as a biocide/pesticide.

Richard Denison from the Environmental Defense Fund noted that there have been beneficial materials in the past that were touted as non-hazardous, that years later were found to have a "dark side" (think: asbestos). EDF aims to determine hazards before the materials are throughout our environment, and wants to insure safety in the development phase. As an example, Ag nanoparticles are excellent antibacterial agents, but if those nanoparticles enter sewage treatment centers via clothes washing machines they could kill beneficial bacteria. Clearly there is not much science on the health and environmental risks of nanomaterials or their manufacture. Policies have even changed with administrations — in 2007 the EPA required no new reviews for nano forms of existing materials, but since 2009, nano forms of existing materials for significant new uses will be subject to EPA notification/review (this is not retroactive to any nanoproduct before 2009, however).

NIST discussed only nanomaterials where at least two dimensions are 1-100nm. Of all current nanomaterial products, Ag nanoparticles make up a significant majority of total, used as antimicrobials in numerous applications from catheters to socks and washing machines. Carbon, titanium, and zinc are also important — titanium oxide and zinc oxide nanoparticles are used is some sunscreen and cosmetic products, for example. The current NIST standards have been made with gold particles (AFM, SEM, TEM, and suspensions for light diffraction), as stable silver particles are hard to produce and keep in a stable composition. One NIST presentation pointed out that nanoparticles actively interact with their environments.

Despite wide agreement that there are perceived and real risks, there are few studies on nanoparticle effect on health and safety — so today perceived risks dominate, often resulting in the public fearing (the unknown) nanoparticles. To make this more confusing, some of the studies may not have validated the contamination vs. the major component in the nanoparticle, further confusing the issue as to where the risk originates. One example is a zero valent iron nanoparticle suspension in development as an anti-cancer agent, which has been pulled from development until risks can be properly evaluated. NIST has been developing standards for particle which is required to start risk assessments of nanomaterials: (1) size, shape, volume; (2) chemical composition and contaminants; and (3) surface chemistry and charge.

John Busbee from the Air Force Research Lab said that the AFRL is now interested only those nanomaterials that have shown technical viability and manufacturing feasibility demonstrated — no longer are concept particles being pursued due to the poor track record of these materials becoming reproducible realities. The first nanomaterials in use by AFRL are those that are replacing traditional materials (e.g., C nanoparticles replacing C powder in solder), but they are now moving to novel applications of these materials.

Scott McNeil of the National Cancer Institute reviewed several nanomaterials that are being evaluated, or have in fact been approved by the FDA for cancer treatments. These particles have numerous substituents, including targeting molecules, cancer treatment drugs, and a PEG shield. He showed that certain particle attributes make it more effective in treating cancer without being harmful to the body. PEG keeps the particle hydrophilic, key to protecting it from the body’s immune system. Particle size will determine if it is accumulated in the spleen or liver (particles 30-220nm are best). When properly formulated, an anti-cancer drug attached to a nanoparticle will be effective at 1/10th the dose of the same drug not attached to the nanoparticle. Studies have also shown that an anti-cancer drug attached to a nanoparticle is safe at a dose that is 3× the lethal dose of non-particle attached drug. Thus, although NCI wants to insure that all nanomaterials pose no ESH issues, they also want to collaborate with the FDA and help companies bring new drugs to market that can treat cancer so effectively.

Travis Earles of the US Office of Science and Technology Policy shared the current administration’s views and priorities with respect to nanotechnology. The administration wants to encourage innovation and acknowledges the need to minimize risk. He discussed the National Nanotech Initiative that is funding basic science that leads to innovation that can lead to start-ups which hopefully becomes manufacturing (in the US) — and that all leads to new economic growth.

Bryan Monroe from Life Technologies (Invirogen) reviewed the biomed pharma challenges and translated these into lessons-learned for nanotechnology companies. Efforts to protect, he said, can cut off from public science — i.e., IP paralysis.

The forum held two sessions of "Rapid Fire" presentations, 7min each with questions afterwards, where researchers could bring ideas to the forum, generate interest, input, and new ideas:

  • Prof. Erik Richman discussed using zebrafish embryos with nanoparticles, and the difficulty in determining exactly where inside the embryo the nanoparticles reside.
  • Mike Jespersen (AFRL) discussed the interesting characteristics of nanoparticles certain surface groups (e.g. PEG) that cause the material to act as a liquid.
  • Donald Baer (Pacific Northwest National Laboratory) showed data on Fe metal core particles with oxide shells. Particles varied too much from batch in manufacturing; and the changed properties with time (low shelf life), some of this was due to contaminants that were not originally well controlled.
  • Prof. John Conley talked about "greener" nanowires. Currently nanowires are grown and then moved into place, leaving the majority as waste. His approach selectively grows wires only where you need them, ZnO or Au seed, pattern & grown. Unfortunately, this requires carbonizing resist, which requires 800-900°C.
  • Grad student Matt Beekman discussed a method of using aqueous solutions to make spin-on thin films of HfOx and similar materials for ICs.
  • Paul Schuele discussed his challenges at Sony in nanomanufacturing for large-scale electronics (think large flat-panel TVs). The customers and people that manufacture the electronics don’t care about "cool"; manufacturing wants lower cost, higher performance, well characterized, and low yield risk. Learning curves are steep to making enough (>83M) yielding devices on a 3′×4′ substrate.

 


Karey Holland, Ph.D., managing partner at Techcet Group, has 25 years of experience in semiconductor technology, including: CMP equipment company SpeedFam-IPEC; IBM (where she contributed to interconnect technology development and manufacturing introduction of IBM’s 4Mb DRAM); Sematech’s deep-UV lithography Micrascan II project; and Motorola’s microprocessor and memory technology group. Contact: kholland@Techcet.com.

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