Unveiling nanoplastic release from single-use eyedrop vials: A particle-based approach for identification and...

Area of Science:

• Environmental Science
• Materials Science
• Ophthalmology

Background:

• Microplastics, specifically micro- and nanoplastics (MNPs), have been detected in ocular tissues, indicating potential risks to eye health.
• The sources, quantity, and characteristics of MNPs in ocular exposure routes, such as eye drops, are not well understood.

Purpose of the Study:

• To investigate the release of synthetic polymers from commercial disposable eye-drop containers.
• To characterize the abundance, morphology, and size distribution of MNPs released from eye drops.
• To evaluate the suitability of different analytical techniques for MNP quantification in small sample volumes.

Main Methods:

• Pyrolysis-gas chromatography-mass spectroscopy (Pyr-GC/MS) was used to detect synthetic polymers.
• Single particle-based techniques, including surface-enhanced Raman spectroscopy (SERS) and scanning electron microscopy (SEM), were employed for MNP characterization.
• Analysis focused on particles released upon opening containers and pre-existing particles.

Main Results:

• Thousands of MNPs were released from eye-drop containers upon opening, with 88% measuring less than 5 μm.
• Pyr-GC/MS was less effective for quantifying low concentrations of MNPs compared to single particle techniques.
• Oxygenated MNPs were detected, suggesting potential for increased ocular toxicity.

Conclusions:

• Commercial eye drops represent a direct exposure pathway for MNPs to the human eye.
• Particle-based analytical methods are crucial for accurately characterizing nanoscale plastic particles.
• Further research is needed to assess the full implications of MNP exposure via eye drops on ocular health.