Amid growing alarm over the plastic that pollutes our environment, biomedical and optics researchers at the 人妻少妇专区 are working to better understand the prevalence of microplastics in drinking water and their potential impacts on human health.
They are collaborating with , a company that uses nanomembrane technology initially developed at the University, to devise ways to quickly filter and identify particles of plastic 5 mm or smaller in drinking water samples. They will then test the ability of these particles to cross a microscale barrier that simulates the lining of a human intestine.
鈥淲e want to see to what extent the particulates that you consume in your drinking water can pass through your gut and into your other organs,鈥� says Greg Madejski, a postdoctoral fellow in the laboratory of , professor of . Madejski is coordinating the research with the lab of , professor of . Both McGrath and Knox are affiliated with the Materials Science Program.
Microplastics are used as ingredients in cigarette filters, textile fibers, and cleaning or personal care products. Others result when larger plastic items are worn down by sun, wind, and waves. They can be found on mountaintops and at the bottom of the oceans; in the air we breathe and in the water we drink. Exactly how many microplastics are absorbed by humans, and how much harm it is causing them has been hard to assess because the particles鈥� below 100 microns鈥攁re so small and difficult to detect.
鈥淭hese are particles that you couldn鈥檛 pick up with tweezers; that you can鈥檛 even see with the naked eye,鈥� Madejski says. They elude the 鈥渢raditional method of skimming the surface of water with a plankton net and collecting everything,鈥� he says.
Instead the researchers will filter water through sheets of silicon nitride a hundred times thinner than the diameter of a human hair. These SiMPore nanomembranes, based on prototypes initially created in the McGrath lab, have micron-sized slits in them. 鈥淭hat allows us to catch micron-sized debris,鈥� Madejski says. 鈥淎nd because the sheets are so thin, you can filter a significant amount of water through them without a lot of pressure.鈥�
The layer of microscopic debris that accumulates on the surface of the membranes is analyzed in various ways to determine how much of it consists of microplastic particles.
The particles can be stained with Nile Red dye, for example, which adheres to plastics. Raman microscopy, used in the Knox lab, shines a bright laser on the material to obtain chemical bond information鈥攂asically 鈥渁 molecular fingerprint of what that material is,鈥� Madejski says. 鈥淚t doesn’t work as well with fluorescent material, which many plastics are, but it can clearly identify 10-micron polystyrene beads, for instance.鈥�
The researchers also hope to use X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy techniques to further study the composition of microplastic particles.
鈥淭he beauty of nanoscale membranes is you can adapt them for a wide range of characterization tools,鈥� Madejski says.
Particles that are identified as microplastics will be separated out and 鈥渇ed鈥� to Caco2 human epithelial cell lines that are widely used as a model of the intestinal epithelial barrier. This will help determine the extent to which the particles are absorbed into the body.
Working with David Rowley of the , water samples are being analyzed at every stage of the city鈥檚 35-mile long gravity-fed water purification and supply system, which stretches from high elevation Hemlock Lake, where the city draws its water, through pipes and reservoirs, and ultimately reaching destinations like the drinking fountains and faucets in the labs and hallways of Goergen Hall on the University鈥檚 River 人妻少妇专区.
There is an urgency to learning more about the prevalence of microplastics and their potential impacts on human health, says Madejski, who recently attended a workshop on microplastics at the Woods Hole Oceanographic Institute.
鈥淥ne thing to keep in mind is that over the last 70 years or so we鈥檝e produced about 4 billion tons of plastic; in the next decade or so, we鈥檙e due to double that amount,鈥� Madejski says.
The project is funded with a award, which provides early-stage capital for technology commercialization. The program allows US-owned and operated small businesses to engage in federal research and development that has a strong potential for commercialization.
