Core–Shell Au@Nanoplastics as a Quantitative Tracer to Investigate the Bioaccumulation of Nanoplastics in Freshwater Ecosystems

Abstract

Studies on the adverse effects of nanoplastics (NPs, particle diameter <1000 nm) including physical damage, oxidative stress, impaired cell signaling, altered metabolism, developmental defects, and possible genetic damage have intensified in recent years. However, the analytical detection of NPs is still a bottleneck. To overcome this bottleneck and obtain a reliable and quantitative distribution analysis in complex freshwater ecosystems, an easily applicable NP tracer to simulate their fate and behavior is needed. Here, size- and surface charge-tunable core–shell Au@Nanoplastics (Au@NPs) were synthesized to study the environmental fate of NPs in an artificial freshwater system. The Au core enables the quantitative detection of NPs, while the polystyrene shell exhibits NP properties. The Au@NPs showed excellent resistance to environmental factors (e.g., 1% hydrogen peroxide solution, simulating gastric fluid, acids, and alkalis) and high recovery rates (>80%) from seawater, lake water, sewage, waste sludge, soil, and sediment. Both positively and negatively charged NPs significantly inhibited the growth of duckweed (Lemna minor L.) but had little effect on the growth of cyanobacteria (Microcystis aeruginosa). In addition, the accumulation of positively and negatively charged NPs in cyanobacteria occurred in a concentration-dependent manner, with positively charged NPs more easily taken up by cyanobacteria. In contrast, negatively charged NPs were more readily internalized in duckweed. This study developed a model using a core–shell Au@NP tracer to study the environmental fate and behavior of NPs in various complex environmental systems.

Integrated Passive Sensing Chip for Highly Sensitive and Reusable Detection of Differential-Charged Nanoplastics Concentration

“…This interaction allows the sulfonic acid group’s hydrogen ions (H + ) to separate from the molecule and combine with water molecules to form hydroxide ions (OH – ) in solution. Based on the ionization of the above two groups, the ionization of PS-NH 2 is more vital than that of PS-SO 3 H, that is, the change of microwave parameter response characteristics of PS-NH 2 is also more substantial than that of PS-SO 3 H. However, both PS-NH 2 and PS-SO 3 H exhibit partial weak ionization in DI water, and most of them still exist in molecular form . Therefore, the resistance characteristics of NPs play a significant role in the variation of microwave parameters, which is the reason for the increase in resonant frequency with the increase of concentration.…”

“…It verified that electrical parameters can be used to detect the concentration and size of NPs and provides a feasible solution for detecting NPs in the microwave field. Based on the characteristics of NPs, such as small particle sizes, different shapes and chemical compositions, easy aggregation, and deposition, the detection of NPs in the environment in the field of environmental sciences is still a challenge at present . Therefore, this paper studies the detection of NPs under controlled conditions in the laboratory, aiming to provide some reference and guidance for the study of NPs in the environment.…”