Metrology for innovative nanoparticles

Short Name: Innanopart, Project Number: 14IND12
Nanoparticles
Coordinator

Accurate methods for measuring nanoparticle concentrations and surface chemistry


The global nanoparticle market has developed into a multi-billion Euro industry, exploiting some unusual properties of various types of tiny, highly functional materials. Applications range from catalysis, drug delivery, semiconducting quantum dots for displays, to advanced coatings. However, market growth has been hindered, in part, by inefficient, and therefore slow and expensive, production processes. Typically, over half the nanoparticles produced for high-performance applications fail to meet specifications, making the cost of validating nanomaterials as high as € 2000 per sample.

 

Europe could set the standards for this emerging industry, spearheaded by its well-established production and user base. Indeed, in 2016 the EU Commission challenged manufacturers to state the composition of nanomaterials, and these products were set to become subject to EU regulation. However, without validated measurement methods, Europe’s industries were not best placed to offer such assurances.

 

Optimising and reproducing nanoparticles requires accurate measurement of concentration but existing methods relied on standards not traceable to the SI; no primary methods or certified reference materials were available. Particle number concentration measurements were also affected by the tendency for some nanoparticles to clump together. Also, nanoparticle surfaces are sometimes engineered to provide specific properties, yet no sufficiently accurate method was available for measuring chemical composition and thickness of nanoparticle surface layers.

 

The project developed and validated accurate protocols for measuring particle number concentrations in liquid suspensions, offering higher than 90 % accuracy compared to 50 % for existing methods. As a world first, spherical reference materials in the size range between 1 nm to 1000 nm were characterised and validated. The project also developed accurate methods to determine number concentration of particles in agglomerated states and for measuring number concentration of non-spherical particles. Next, accurate methods for measuring surface chemistry and the thickness of surface coatings of particles were developed. Two inter-laboratory studies were conducted, then the resulting validated procedures disseminated as good practice guides.

 

The good practice guidance was further developed in the follow-on ISOCONCur project, as an International Organization for Standardization technical report.

 

The new particle number concentration measurement method enabled Malvern Panalytical, a manufacturer of analytical instruments, to validate the performance of a prototype of its Zetasizer Ultra instrument, so enabling the company to offer accurate particle number concentration measurement as a new feature. LGC subsequently offered the reference material validated in the project as the world's first nanoparticle quality control material for number-based concentration. Rapid particle number concentration measurements also enabled Dolomite Microfluidics, a solutions provider to the pharmaceutical industry, to revolutionise its nanoparticle formulation process, speeding typical formulation cycles from two weeks to just two hours.

 

The overall effect of the guidance, standards and methods developed has been estimated by the consortium as likely to reduce nanoparticle production and measurement costs by an order of magnitude. Reliable control of nanoparticle production quality is speeding development of new products and applications and helping support EU regulatory requirements. Standardisation will, in due course, enhance consumer acceptance, enabling European industry to be positioned to develop new nanoparticles and nano-based applications with superior market appeal.

Project website
Other Participants
Commissariat à l'énergie atomique et aux énergies alternatives (France)
Stichting Wageningen Research (Netherlands)
Technische Universitaet Wien (Austria)
The University of Birmingham (United Kingdom)
Universita Degli Studi del Piemonte Orientale "Amedeo Avogadro" (Italy)