Researchers from MIT and the Federal University of Goiás (FUG?) recently discovered how to use nanoparticles and ultraviolet (UV) light to extract pollutants, like pesticides and endocrine disruptors, from soil and water.
The discovery was a happy accident that spun out of cancer research. The goal was to develop nanoparticles that could be used to deliver drugs to cancer cells. Ferdinand Brandl of MIT had synthesized a polymers that could carry the medication and be cut by UV light to administer the dose.
However, the team began to question the polymer’s suitability for drug delivery for two reasons; UV will damage tissue cells and it is unable to penetrate into the skin. Since the UV will be unable to make it to the in vivo polymers, there will be no practical means to release the medication.
The research team decided to shift their application for the polymer after learning that UV light was used to disinfect water in some treatment plants, reports Jonathan Mingle, with MIT News.
“We thought if they are already using UV light, maybe they could use our particles as well,” Brandl said. “Then we came up with the idea to use our particles to remove toxic chemicals, pollutants or hormones from water, because we saw that the particles aggregate once you irradiate them with UV light.”
Their paper published in Nature Communications reads; “To the best of our knowledge, it is the first time that the interactions of small molecules with pre-formed nanoparticles can be directly measured.”
Absorbing Pollutants
The team’s Nanoparticles were made from synthesized co-polymers made from polyethylene glycol and polylactic acid (PLA). Similar to a cell membrane, the nanoparticles have a hydrophobic core and a hydrophilic shell.
The hydrophilic shell allows the particles to be suspended in water. Meanwhile, the hydrophobic pollutant molecules are attracted to the hydrophobic nanoparticles and are absorbed into the surface. The hydrophilic shell is shed when exposed to UV light. What remains of the particles clump together into the macro scale allowing them to be removed by filtration. The PLA polymers left behind is biodegradable.
The researchers have already used the method to extract phthalates (hormone disrupting chemicals used to soften plastic) from wastewater. They’ve also successfully removed polycyclic aromatic hydrocarbons (carcinogenic compounds formed from incomplete combustion of fuels) from contaminated soil among other things, Mingle writes.
Further Applications for the Nanoparticles
Co-author Nicolas Bertrand noted that DDT pesticide is an example of a widely used pollutant, outside the U.S., that could be removed from soil with use of their nanoparticles.
Bertrand speculates that using nanoparticles, additional applications could include medical analysis and even replacing organic solvents used in making paint thinners.
The study suggests the potential of adapting nanoscale drug-delivery techniques developed for use in environmental remediation.
“That we can apply some of the highly sophisticated, high-precision tools developed for the pharmaceutical industry and now look at the use of these technologies in broader terms, is phenomenal,” said Frank Gu, expert in nano-engineering for health care and medical applications.
Ferdinand Brandl and Nicolas Bertrand are former postdocs in the laboratory of Robert Langer, the David H. Koch Institute Professor at MIT’s Koch Institute for Integrative Cancer Research. Eliana Martins Lima, of the Federal University of Goiás, is the third co-author.
For more information on their paper, visit www.nature.com.