Size, polyglycerol grafting, and net surface charge of iron oxide nanoparticles determine their interaction and toxicity in Caenorhabditis elegans

Yajuan Zou; Yutaka Shikano; Yuta Nishina; Naoki Komatsu; Eriko Kage-Nakadai; Masazumi Fujiwara

doi:10.1016/j.chemosphere.2024.142060

Size, polyglycerol grafting, and net surface charge of iron oxide nanoparticles determine their interaction and toxicity in Caenorhabditis elegans

Chemosphere. 2024 Apr 20:358:142060. doi: 10.1016/j.chemosphere.2024.142060. Online ahead of print.

Authors

Yajuan Zou¹, Yutaka Shikano², Yuta Nishina³, Naoki Komatsu⁴, Eriko Kage-Nakadai⁵, Masazumi Fujiwara⁶

Affiliations

¹ Graduate School of Natural Science and Technology, Okayama University, Kita-ku, Okayama, 700-8530, Japan.
² Institute of Systems and Information Engineering, University of Tsukuba, Tsukuba, Ibaraki, 305-8573, Japan; Center for Artificial Intelligence Research (C-AIR), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan; Institute for Quantum Studies, Chapman University, Orange, CA, 92866, USA.
³ Graduate School of Natural Science and Technology, Okayama University, Kita-ku, Okayama, 700-8530, Japan; Research Core for Interdisciplinary Sciences, Okayama University, Kita-ku, Okayama, 700-8530, Japan.
⁴ Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
⁵ Department of Nutrition, Graduate School of Human Life and Ecology, Osaka Metropolitan University, Sumiyosi-ku, Osaka, 558-8585, Japan; Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8507, Japan.
⁶ Graduate School of Natural Science and Technology, Okayama University, Kita-ku, Okayama, 700-8530, Japan. Electronic address: masazumi@okayama-u.ac.jp.

PMID: 38648981
DOI: 10.1016/j.chemosphere.2024.142060

Abstract

The widespread application of engineered nanoparticles (NPs) in environmental remediation has raised public concerns about their toxicity to aquatic organisms. Although appropriate surface modification can mitigate the ecotoxicity of NPs, the lack of polymer coating to inhibit toxicity completely and the insufficient knowledge about charge effect hinder the development of safe nanomaterials. Herein, we explored the potential of polyglycerol (PG) functionalization in alleviating the environmental risks of NPs. Iron oxide NPs (ION) of 20, 100, and 200 nm sizes (IONS, IONM and IONL, respectively) were grafted with PG to afford ION-PG. We examined the interaction of ION and ION-PG with Caenorhabditis elegans (C. elegans) and found that PG suppressed non-specific interaction of ION with C. elegans to reduce their accumulation and to inhibit their translocation. Particularly, IONS-PG was completely excluded from worms of all developmental stages. By covalently introducing sulfate, carboxyl and amino groups onto IONS-PG, we further demonstrated that positively charged IONS-PG-NH₃⁺ induced high intestinal accumulation, cuticle adhesion and distal translocation, whereas the negatively charged IONS-PG-OSO₃^- and IONS-PG-COO^- were excreted out. Consequently, no apparent deleterious effects on brood size and life span were observed in worms treated by IONS-PG and IONS-PG bearing negatively charged groups. This study presents new surface functionalization approaches for developing ecofriendly nanomaterials.

Keywords: Accumulation; C. elegans; Distribution; Iron oxide nanoparticles; Polyglycerol functionalization; Toxicity.