Stacey (“Stace”) and Bryan Harper got into the microplastics business in a small way. A very small way. They started out as nano-scientists with an interest in how the different features of nanomaterials, their size, shape and surface chemistry, affect their properties. With the recent concerns about microplastics in the environment, they began to apply their nano-knowledge to numerous ecotoxicology projects focused on plastics. Their ability to make nanoscale plastics using their cryo-mill, think high tech rock grinding machine that uses liquid nitrogen to make materials more fragile and susceptible to cracking apart, has allowed the lab to make all kinds of nanoplastics for ecotoxicity studies. The bench top had dozens of vials of containing nano polyactic acid and polypropylene plastic particles among others.
One of the difficulties in studying nanoplastics is that they are so small that they are hard to identify and to count. The Harper Lab has a NanoSight instrument, which uses laser light to illuminate the small particles and allows them to calculate their size based on the
particle’s Brownian motion. The attached camera system, with a known field of view, allows them to know the concentration of nanoparticles in a sample.
Using the cryo-mill produced nanoplastics at known concentrations, Stace and Bryan and their collaborators at OSU have been able to conduct a number of nanoplastic ecotox studies. Some have been small bench-top microcosms with algae and microscopic organisms to determine the ecological effects of nanomaterials. They have also contributed to the first study that looked at the effects of nanoplastics fed to mice. This work is critical, as we become more aware, and perhaps convinced, that the human health effects of nanoparticles are likely of more concern than macro- or microplastics, given their ability to pass through biological membranes.
Like many of us, Stace and Bryan are interested in helping coordinate methods among microplastics researchers. They are part of a grant submitted to the National Science Foundation for Accelerating Research through International Network-to-Network Collaborations – which is a platform through which methodologies could be coordinated across labs. They also have initiated a consortium of folks that are performing studies on tire wear particles, specifically the cryo-milled tire tread particle samples provided to many of us by the US Tire Manufacturer’s Association. I was fortunate to be invited to join the group and look forward to our first discussion in April!