Wedoany.com Report on Feb 26th, As a novel detection tool, the optical sieve enables rapid detection, size measurement, and counting using a standard microscope by capturing nanoplastics within microcavities and observing resulting color changes.
The detection of microplastics and nanoplastics (MPs and NPs) has long faced the challenge of insufficient rapid and reliable methods, which affects the accuracy of results. Researchers from Germany and Australia have collaborated to develop a simple and fast method for nanoplastic detection, which holds promise for overcoming the limitations of existing techniques such as FTIR and SEM, which are time-consuming and expensive.
This method, known as the optical sieve, utilizes strips with microscale cavities and a conventional optical microscope. The researchers fabricated the strips using a high-refractive-index material and incorporated multiple arrays of micropores, referred to as Mie voids. These cavities interact with light, producing specific colors based on their size through the phenomenon of optical resonance.
When a droplet containing nanoplastics is placed on the optical sieve, the cavities capture particles with matching diameters, while particles that are too large or too small are washed away. Empty cavities exhibit characteristic colors under illumination, and the color changes immediately when a particle enters. Scientists can observe this difference using a standard microscope, without relying on advanced detection technologies.
The optical sieve not only detects nanoplastics in liquids but also allows for rapid measurement and counting of particles. The researchers infer particle size by analyzing cavities with the highest occupancy rates and improve accuracy using statistical occupancy analysis. For particle counting, they tally the number of occupied cavities and differentiate between empty cavities and those containing varying numbers of particles through CIE-based colorimetric analysis.
Overall, the optical sieve technology enables faster in-situ detection and characterization of nanoplastics in environmental and biological liquid systems. It does not require highly trained personnel and can be used in the field with portable, low-cost equipment, demonstrating significant potential. Future research will test liquid samples containing nanoplastics of different sizes and shapes.
