@inproceedings{01H2R0RDHMY0EY1G9MTZKSXC4A,
  abstract     = {{The possible ecological impact of nanoplastics (NPs, dimensions < 1 µm) differs from microplastics
(MPs), which are usually limited to the digestive organs of the affected organisms. Studies show that
the rate of transport over cellular barriers increases as the plastic particle size decreases, and also the
transportation process (through endocytosis or through paracellular routes) depends on the particle size.
The aim of this project was to develop a method to label and visualize nanoplastics in their interaction
with marine primary producers and consumers. This entails both the possible adsorption and absorption,
to study uptake mechanisms, retention rates and possible accumulation.
The method development consists of different parts. First, the label-technique was optimized, using
absorptive swelling as described by Karakolis et al., (2019), with the commercial dye ‘IDye’ (ex. 669 nm,
em. 550 nm). This dye has shown extreme stability for fluorescence imaging purposes and is compatible
with STED (Stimulated Emission Depletion) microscopy. Next, the suitability of this labelling technique
for plastic-toxicity testing was checked. The acute toxicity of the dye towards algae and copepods was
tested using OECD protocols. A dose-response curve was built around the assumed exposure
concentration (1.4 x 10-8 mg ml-1
), and showed that the EC50 (0.0277 mg ml-1)
, and the EC10 (0.00836
mg ml-1
) for marine algae are located far above this . Furthermore, to account for false positives and
negatives in image analysis, the leaching of the dye from the particles, and the longevity of the
fluorescence of the particles is analyzed as a function of time. The effects of the labelling on the plastic
particle characteristics, was compared to the non-labelled plastics, using FTIR, Single Particle Tracking
(SPT) and a Tecan plate reader.
This study focused on the nanoparticles smaller than 200 nm, the size-range at which different particles
can no longer be distinguished due to the resolution limit of optical microscopes. To enable the
visualization of these particles, we worked with the super resolution STED-microscope. We were able
to acquire significant increases in resolution. To visualize the labelled nanoplastics in interaction with
the autofluorescent, phytoplankton species, we used FLIM (Fluorescence Lifetime Imaging Microscopy).
This technique allowed to differentiate between phytoplankton species and plastics due to differences
in the exponential decay rate of the photon emission.}},
  articleno    = {{P-Mo076}},
  author       = {{Sioen, Marie and Vercauteren, Maaike and Blust, Ronny and Janssen, Colin and Asselman, Jana and Town, Raewyn M.}},
  booktitle    = {{SETAC Europe, 33rd Annual Meeting, Abstracts}},
  issn         = {{2309-8031}},
  language     = {{eng}},
  location     = {{Dublin, Ireland & online}},
  pages        = {{P-Mo076:76--P-Mo076:77}},
  title        = {{Visualization of labelled nanoplastics in algae and copepods, using Stimulated Emission Depletion (STED-)microscopy and Fluorescence Lifetime Imaging (FLIM)}},
  year         = {{2023}},
}