Detection of environmental nanoplastics via surface-enhanced Raman spectroscopy using high-density, ring-shaped nanogap arrays

Sihai Luo; Junjie Zhang; John C de Mello

doi:10.3389/fbioe.2023.1242797

Detection of environmental nanoplastics via surface-enhanced Raman spectroscopy using high-density, ring-shaped nanogap arrays

Front Bioeng Biotechnol. 2023 Oct 24:11:1242797. doi: 10.3389/fbioe.2023.1242797. eCollection 2023.

Authors

Sihai Luo¹, Junjie Zhang¹, John C de Mello¹

Affiliation

¹ Department of Chemistry, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.

Abstract

Micro- and nano-plastics (MNPs) are global contaminants of growing concern to the ecosystem and human health. In-the-field detection and identification of environmental micro- and nano-plastics (e-MNPs) is critical for monitoring the spread and effects of e-MNPs but is challenging due to the dearth of suitable analytical techniques, especially in the sub-micron size range. Here we show that thin gold films patterned with a dense, hexagonal array of ring-shaped nanogaps (RSNs) can be used as active substrates for the sensitive detection of micro- and nano-plastics by surface-enhanced Raman spectroscopy (SERS), requiring only small sample volumes and no significant sample preparation. By drop-casting 0.2-μL aqueous test samples onto the SERS substrates, 50-nm polystyrene (PS) nanoparticles could be determined via Raman spectroscopy at concentrations down to 1 μg/mL. The substrates were successfully applied to the detection and identification of ∼100-nm polypropylene e-MNPs in filtered drinking water and ∼100-nm polyethylene terephthalate (PET) e-MNPs in filtered wash-water from a freshly cleaned PET-based infant feeding bottle.

Keywords: lithography; microplastics; nanoplastics; plasmonics; surface-enhanced Raman spectroscopy.

Grants and funding

The experimental work was undertaken in the NTNU NanoLab with financial support from NTNU, project number 81771118. The Research Council of Norway is acknowledged for the support to the Norwegian Micro and Nano-Fabrication Facility, NorFab, project number 245963/F50. Partial funding for this work was obtained from Norwegian PhD Network on Nanotechnology for Microsystem, which is sponsored by the Research Council of Norway, Division for Science, under contract no. 221860/F60.