New tracer nanoparticles allow scientists to track nanoplastic pollution in freshwater ecosystems

(Nanowerk News) Plastic pollution poses a growing threat to aquatic ecosystems worldwide. Of particular concern are nanoplastics, plastic particles less than 1,000 nanometers in size. Studies show nanoplastics can be toxic to aquatic organisms, causing physical damage, oxidative stress, and developmental issues. However, detecting and quantifying nanoplastics in the environment remains challenging.
To help address this problem, researchers have developed a new type of nanoparticle tracer that allows nanoplastics to be tracked in freshwater ecosystems. As reported in the journal Analytical Chemistry, the tracer nanoparticles have a unique core-shell structure consisting of a gold nanoparticle core surrounded by a polystyrene plastic shell.
The study was published in Analytical Chemistry ("Core−Shell Au@Nanoplastics as a Quantitative Tracer to Investigate the Bioaccumulation of Nanoplastics in Freshwater Ecosystems").
The gold core enables sensitive detection and quantification of the nanoparticles using a technique called single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). The polystyrene shell gives the nanoparticles properties similar to environmental nanoplastics. By studying the behavior of the tracer nanoparticles, the researchers aim to gain insights into the fate of nanoplastics in nature.
“The excellent resistance and high recovery rates of the tracer nanoparticles make them ideal for investigating the distribution and accumulation of nanoplastics in complex freshwater systems,” says Dr. Xian-Zheng Yuan, an author of the study.
A key advantage of the new tracer nanoparticles is the ability to tune their size and surface charge during synthesis. This allows the researchers to mimic different types of nanoplastics found in the environment. The nanoparticles are synthesized using a simple three-step process, with gold nanoparticles first being coated with the polystyrene shell.
The researchers demonstrated the accuracy of the SP-ICP-MS technique for detecting the tracer nanoparticles by comparing calculated and measured concentrations in water samples. They also showed the nanoparticles have excellent stability in conditions mimicking natural aquatic environments.
To evaluate the suitability of the tracer nanoparticles for studies with living organisms, the researchers exposed cultures of duckweed and cyanobacteria to the particles. The experiments revealed differences in accumulation between positively and negatively charged nanoparticles for each species.
“This demonstrates how our tunable tracer nanoparticles can provide quantitative insights into the bioaccumulation behavior of nanoplastics with different surface properties,” explains Dr. Yuan.
The researchers conclude that the core-shell gold-polystyrene nanoparticles are a highly promising new tool for investigating the fate and impacts of nanoplastics in freshwater ecosystems. By providing a reliable way to simulate and track plastic nanoparticles, the tracers will support critical environmental research.
“Our tunable tracer method overcomes previous limitations in studying nanoplastics in complex natural systems. The core-shell nanoparticles developed here should enable deeper insights into the distribution, accumulation, and toxicity of plastic nanoparticles in the aquatic environment,” remarks Dr. Yuan.
Going forward, the researchers plan additional studies to explore how factors like nanoparticle shape, corona formation, and biofilm interactions influence the behavior of nanoplastics in the environment. They are also working to adapt the tracer method for studying nanoplastics in other systems such as soil.
The threat posed by plastic pollution continues to grow globally, underscoring the need for improved ways to investigate nano-sized plastic particles in the environment. By providing an effective simulation and quantification method, this new tracer nanoparticle technology represents an important step toward better understanding and managing the risks of nanoplastics to freshwater ecosystems.
Source: Chinese Academy of Sciences (Note: Content may be edited for style and length)
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