Celebrating 20 Years of the Nanotechnology Research Center: Measuring the Small Things

Summary

Nanotechnology uses science to create very small materials. Engineered nanomaterials are made to have properties that are different from a larger form of the same material. Usually, this change in properties happens when the material gets smaller, so most engineered nanomaterials have at least one dimension that measures less than 100 nanometers. Although this change makes the materials useful for creating new products that benefit society, their small size presents challenges to protecting worker safety and health.

When the Nanotechnology Research Center (NTRC) first began in 2004, one of its biggest challenges was understanding exactly what to measure and how to measure it. Today, the NTRC conducts research and develops recommendations on appropriate ways to make measurements of nanomaterials in workplaces, contributes to the qualification and proper use of reference materials, and contributes to development of consensus standards.

Measurement Highlights

Workplace Measurements

Historically, exposures have been measured as the mass of a substance in air, but nanomaterials are so small that they have very little weight. So at first, it was unclear which nanomaterial properties to measure because we did not know how they each impacted health effects seen in animal studies. Nanomaterial properties such as particle size and shape, surface area, and surface chemistry (or activity) might be more predictive than particle mass for potential health outcomes.

The NTRC established guidance on a practical and reproducible method to perform exposure assessments in the workplace through the Nanoparticle Emission Assessment Technique (NEAT) model. This was done as part of its Approaches to Safe Nanotechnology publication. The method used portable, direct-reading instruments and filter-based air samples. This was later updated to address interferences from incidental background nanomaterials and called NEAT 2.0.1

In 2022, NIOSH published a technical report, Occupational Exposure Sampling for Nanomaterials, on the best ways to sample for nanomaterials in the workplace. The report provided general guidance for all nanomaterials and specific guidance for nanomaterials with recommended exposure limits, including Carbon Nanotubes and Nanofibers, Titanium Dioxide, and Silver Nanomaterials; 2

Reference Materials

Reference materials are used to calibrate instruments or assess measurement methods.3 NIOSH recognized early on that reference materials help establish a strong foundation to accurately measure exposures in workplaces and conduct laboratory research studies.4 National Metrology Institutes are government bodies that make reference materials. NIOSH researchers worked closely with the U.S. National Institute of Standards and Technology and National Research Council – Canada. They ensured that some reference materials produced by the metrology institutes would include properties that best support nanotechnology research goals identified by NIOSH and its partners. Some examples of reference materials that NIOSH helped develop include:

• Titanium dioxide nanomaterial Standard Reference Material 1898 (nist.gov)
• Cellulose nanocrystal suspension Cellulose Nanocrystal Suspension Certified Reference Material (canada.ca)

Consensus Standards

During the emergence of nanotechnology, NIOSH also recognized that standards would help ensure consistency and quality in measurements for workplace exposure assessments, laboratory research, and all areas of occupational health and safety. NIOSH is active in several technical committees committed to developing standards for nanotechnology:

• ASTM E56 Nanotechnology Committee E56 on Nanotechnology (astm.org)
• ISO TC229 Nanotechnologies ISO/TC 229 – Nanotechnologies

Looking to the Future of Measuring Nanomaterials

Measurement development has progressed over the last 20 years. In 2004, we were uncertain about which properties to measure or how to measure an engineered nanomaterial. Now we have many instruments, reference materials, and standards to use that will help protect workers.

Looking forward, we recognize the growing complexity in nanomaterials such as biological nanomaterials, systems made of multiple nanomaterials, and self-forming nanomaterials. Some workplaces are already using new, advanced materials that include nanomaterials and have their own unique characteristics. We also know that changes in workplace technologies, such as 3D printing, will present new measurement challenges.

NTRC 20th Anniversary Blogs

Over the past nine months, we've highlighted our critical work with this blog series, but we've only scratched the surface. Revisit some of our earlier posts below and be sure to keep up with us on the NTRC webpage.

• Looking to the Past and the Future of NIOSH Nanotechnology Guidance
• NIOSH Global Collaborations on Workplace Safety of Nanomaterials
• Sweating the Small Stuff: 20 years of NIOSH Research on Engineering Controls for Nanotechnology
• Celebrating 20 Years of Research: Highlights From NIOSH's Nanotechnology Research Center's Field Studies Team
• The Nanotechnology Research Center Carbon Nanotube Registry
• NIOSH Risk Assessment of Engineered Nanomaterials
• Celebrating 20 Years of the Nanotechnology Research Center: Highlights from Engineering Controls and Personal Protective Equipment
• When Nanoparticles Blow Up— Explosion Hazards of Nanoparticles
• NTRC Marks 20 Years of Studying Nanotoxicology: Highlights from the Toxicology and Internal Dose Team

Concluding the 20th Anniversary Celebration of the NTRC

With Nanotechnology Day right around the corner on October 9, it's fitting that we're closing out our blog series and 20th anniversary celebration of the NTRC.

Join us at the 2024 Nanotechnology Health and Safety Summit on October 9–10 at the University of Cincinnati or attend online. This summit will cover safety and health topics such as additive manufacturing and advanced materials, semiconductors, lithium-ion battery technology, and nanotechnology. It's a great opportunity to hear from experts in industry, academia, and government sectors.

Registration for the summit closes October 1st. If you're unable to join, look for a future blog summarizing exciting insights and key discoveries from the event.

The NTRC remains committed to offering research-based guidance to protect workers and meet the needs of the ever-changing field of nanomaterials and related emerging technologies. We continue to seek and gather feedback and adapt to the evolving landscape of technological advancements and emerging worker safety challenges. Our aim is to bridge knowledge gaps and recommend practical actions. If you have input or suggestions about guidance or research needs, contact nano@cdc.gov.

Author Information

Jay Vietas, PhD, CIH, CSP, is the co-manager of the NTRC and branch chief of the Emerging Technologies Branch in the NIOSH Division of Science Integration.

Aleksandr Stefaniak, PhD, CIH, is the co-coordinator of the NTRC and a research industrial hygienist of the Field Studies Branch in the NIOSH Respiratory Health Division.