Single-Particle Resolution Fluorescence Microscopy of Nanoplastics

Area of Science:

• Environmental Science
• Analytical Chemistry
• Toxicology

Background:

• Nanoplastic detection is challenging due to their small size, limiting understanding of their environmental and health impacts.
• Conventional fluorescence microscopy lacks the resolution to accurately localize and quantify nanoplastics in biological tissues or environmental samples.

Purpose of the Study:

• To develop and validate novel labeling techniques for nanoplastic imaging using stimulated emission depletion (STED) microscopy.
• To achieve high-resolution imaging of nanoplastics, enabling precise localization and quantification in complex matrices.

Main Methods:

• Developed three nanoplastic labeling methods: passive sorption, swell incorporation, and covalent coupling of STED-compatible dyes.
• Utilized stimulated emission depletion (STED) microscopy for super-resolution imaging of labeled nanoplastics.
• Assessed dye labeling longevity in various relevant media and conditions.
• Applied STED imaging to detect nanoplastics in the model organism *Caenorhabditis elegans*.

Main Results:

• Successfully resolved nanoplastics as small as 50 nm in size, irrespective of shape and composition.
• Demonstrated the stability and longevity of dye labeling under diverse environmental and biological conditions.
• Achieved non-disruptive, high-resolution imaging and localization of nanoplastics within whole *Caenorhabditis elegans*.

Conclusions:

• The developed labeling techniques coupled with STED microscopy significantly enhance nanoplastic detection and localization capabilities.
• This method offers a powerful tool for accurate quantification of nanoplastics in complex biological and environmental samples.
• Enables more precise exposure studies and toxicological assessments of nanoplastics.