Label-Free Live-Cell Imaging of Internalized Microplastics and Cytoplasmic Organelles with Multicolor CARS Microscopy

Area of Science:

• Cellular biology
• Microscopy techniques
• Toxicology

Background:

• Microplastic (MP) bioaccumulation poses potential health risks.
• Understanding MP cellular dynamics and cytotoxicity is crucial.
• Current methods often require pre-labeling of MPs for imaging.

Purpose of the Study:

• To demonstrate a label-free method for visualizing MPs and cellular structures.
• To investigate the intracellular dynamics and distribution of MPs in live cells.
• To assess the potential of multicolor CARS microscopy for MP toxicity studies.

Main Methods:

• Utilized label-free multicolor coherent anti-Stokes Raman scattering (CARS) microscopy.
• Acquired simultaneous vibrational images of internalized polystyrene (PS) beads and lipid droplets (LDs).
• Tracked the real-time movements and intracellular dynamics of PS beads and LDs in *Caenorhabditis elegans*.

Main Results:

• Successfully visualized and distinguished internalized MPs from native LDs based on their vibrational signatures.
• Identified the precise spatial distribution of ingested PS beads and LDs within live cells.
• Characterized the individual intracellular dynamics and movements of MPs and LDs in real time.

Conclusions:

• Multicolor CARS microscopy offers a label-free approach to study MP-cell interactions.
• The method enables simultaneous imaging and tracking of MPs and endogenous cellular components like LDs.
• This technique can significantly advance research into MP cellular transport and cytotoxicity without pre-labeling.