Labelling of micro- and nanoplastics for environmental studies: state-of-the-art and future challenges

Yin Liu; Jie Li; Bogdan V Parakhonskiy; Richard Hoogenboom; Andre Skirtach; Stefaan De Neve

doi:10.1016/j.jhazmat.2023.132785

Labelling of micro- and nanoplastics for environmental studies: state-of-the-art and future challenges

J Hazard Mater. 2024 Jan 15:462:132785. doi: 10.1016/j.jhazmat.2023.132785. Epub 2023 Oct 14.

Authors

Yin Liu¹, Jie Li², Bogdan V Parakhonskiy², Richard Hoogenboom³, Andre Skirtach², Stefaan De Neve⁴

Affiliations

¹ Department of Environment, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium. Electronic address: Yin.Liu@UGent.be.
² Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent Belgium.
³ Supramolecular Chemistry Group, Centre of Macromolecular Chemistry (CMaC), Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 S4, 9000 Ghent Belgium.
⁴ Department of Environment, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium.

PMID: 37856963
DOI: 10.1016/j.jhazmat.2023.132785

Abstract

Studying microplastics and nanoplastics (MNP) in environmental matrices is extremely challenging, and recent developments in labelling techniques may hold much promise to further our knowledge in this field. Here, we reviewed MNP labelling techniques and applications to provide the first systematic and in-depth insight into MNP labelling. We classified all labelling techniques for MNP into four main types (fluorescent, metal, stable isotope and radioisotope) and discussed per type the synthesis methods, detection methods, influencing factors, and the current and future applications and challenges. Direct labelling of environmental MNP with fluorescent dyes and metals enables simple visualisation and selective detection of MNP to improve detection efficiency. However, it is still an open question how to avoid co-labelling of non-plastic (i.e. non-target, matrix) materials. Labelling of MNP that are intentionally added in the environment may allow semi-automatic detection of MNP particles with high accuracy and sensitivity during studies on e.g. transport and degradation. The detection limit of labelled MNP largely depends on particle size and the type of matrix. Fluorescent labelling allows efficient detection of microplastics, whereas metal labelling is preferred for nanoplastics research due to a potentially higher sensitivity. A major challenge for fluorescent and metal labelling is to develop techniques that do not alter the inherent MNP properties or only do so minimally, in particular the surface properties. Stable and radioactive isotope labelling (¹³C and ¹⁴C, but also ¹⁵N, ²H) of the polymer itself allows to preserve inherent MNP properties, but have been largely ignored. Overall, labelling of MNP holds great promise for advancing our fundamental understanding of the behaviour of plastics, notably the smallest fractions, in the environment.

Keywords: Label induced alterations; Labelling; Leaching; Microplastic detection; Nanoplastics.

Publication types

Review