Researchers at The School of Freshwater Science, University of Wisconsin-Milwaukee, US, are using NanoSight Nanoparticle Tracking Analysis (NTA) from Malvern Instruments to investigate the effects of nanoparticle contaminants on freshwater organisms.

The work, which is at the forefront of nanotoxicity testing, has focused on using the unique size, concentration and visualisation capabilities provided by NTA to monitor how specific changes in nanoparticle surface chemistry influence the impact of the particles on molecular species in environmental media. NTA is used as part of an ensemble of analytical techniques that includes dynamic light scattering (DLS) with the Malvern Zetasizer Nano, which is used for its sizing capabilities and to monitor overall formulation stability.

"The goal of our research is to provide a greater understanding of the influence of nanomaterials on the environment and advance the scientific theory that underpins nanoparticle health and safety," said Dr Klaper, associate professor, School of Freshwater Sciences, University of Wisconsin-Milwaukee.

"Nanoparticles present unique challenges to toxicity testing compared with testing for chemical contaminants because of their particulate nature and novel behaviors. Nanoparticle Tracking Analysis has provided us with an instantaneous way of looking at the behavior of the nanoparticles within a biological medium, providing insight unachievable with alternative analysis techniques."

NanoSight NTA, now part of Malvern Instruments’ nanoparticle characterization portfolio, is a unique method of characterizing nanoparticles within solution. Each particle is individually but simultaneously analyzed by direct observation and measurement of diffusion events. This particle-by-particle methodology produces high resolution results for particle size distribution and concentration, while visual validation provides users with additional confidence in their data. Both particle size and concentration are measured.

Used in concert with additional characterization techniques, such as the Zetasizer Nano, this holistic approach to characterisation provides the breadth of analytical data required to inform the emerging health and safety aspect of nanomaterials before they are released into the environment.

"NTA has allowed us to really focus on how variations among nanoparticles, such as small changes in the surface chemistry, correlate to their behavior within an environmental medium and their interactions within organisms," Dr Klaper said. "One of the great things about the Nanoparticle Tracking Analysis system is the unique visualisation capability which enables real-time empirical insight into key particle behaviour, such as the propensity and rate of aggregation, as opposed to alternative techniques with often lengthy procedures."

The research performed by Dr Klaper and her team is only the first stage in optimizing the potential of the NanoSight NTA system, which has found widespread use in other areas for its unique capability to measure exosomes.

"We’re very interested in exosome research to determine protein changes that may occur once the nanoparticle interacts with the organism," added Dr Klaper. "So we anticipate that the next stage of our research will focus on using the NTA system to investigate how proteins and exuded cellular exosomes vary over time."