Plastic waste has long been considered an escalating crisis on Earth, polluting oceans, rivers, and soils worldwide. While microplastic particles have been the main focus, nanoscale plastic particles (less than one micrometer in size) are emerging as a greater threat due to their ability to penetrate biological barriers such as the skin and the blood-brain barrier.
Detecting these fine particles poses a significant challenge, typically requiring expensive and complex imaging techniques like scanning electron microscopes. The new method overcomes these obstacles by using resonance effects within micro semiconductor holes, called ‘Mie gaps,’ which change color significantly when a nanoscale plastic particle enters them.
When particles fall into these cavities, the reflected light indicates their presence through bright color shifts observable under a simple optical microscope. This not only allows for counting the particles but also determining their size, accelerating analysis and reducing costs without the need for highly trained technicians.
To validate the technique, researchers synthesized environmental water samples by mixing sand, organic materials, and known quantities of spherical nanoscale plastic particles. Future plans include testing real water samples, evaluating non-spherical particles, and distinguishing between types of plastic to expand this technique’s application in environmental and health research.
This innovation opens a new chapter in combating plastic pollution by providing a practical tool for onsite detection of nanoscale plastics, which may soon enable communities, scientists, and policymakers to better understand and mitigate this hidden threat.
