A New Window Into Microplastic Behavior
Microplastics are now found almost everywhere—from oceans and soil to food and drinking water. However, scientists still know relatively little about what happens when these tiny plastic particles enter living organisms. Researchers at the Tokyo University of Science recently developed a new imaging technique that allows them to track microplastics moving through the bodies of living animals in real time.
The team used Second Near-Infrared Fluorescence Imaging, also known as NIR-II imaging. This advanced method allows light to penetrate deeper into biological tissues than traditional imaging techniques. As a result, scientists can directly observe how microplastics travel through the body without performing invasive procedures.
Making Microplastics Glow
To make the particles visible inside the body, the researchers engineered special fluorescent microplastics. They created nanoscale fragments from common plastics such as polyethylene, polypropylene, and polystyrene. The team then labeled these particles with a fluorescent dye called IR-1061, which emits a strong signal in the near-infrared range.
The particles measured between about 30 and 300 nanometers and closely resembled the irregular shapes of environmental microplastics. The researchers also ensured that the particles maintained stable fluorescence for more than 30 days, enabling long-term observation.
Following the Plastic Path
The researchers fed the glowing microplastics to mice and used the imaging system to follow their movement through the digestive tract. The images showed the particles first accumulating in the stomach before gradually moving into the intestines.
Over time, the animals expelled most of the microplastics through feces within about 48 hours. The researchers also observed that smaller particles tended to remain in the intestines longer than larger ones.
A Tool for Future Health Research
This study provides scientists with a powerful new tool for investigating how microplastics interact with living systems. The technique enables real-time, non-invasive tracking, allowing researchers to examine how different types of plastic particles behave inside the body.
As microplastic pollution continues to grow worldwide, methods like NIR-II imaging could help scientists better understand the potential health risks linked to long-term exposure.
