Preparation of fluorescent nanoplastics for kinetic analysis

Abstract

Recently, microplastics (MPs) and nanoplastics (NPs) have been gained attention as environmental problems. MPs are plastic particles with a diameter of 5 mm or less and are present in the environment. They have been detected not only in table salt and drinking water, but also in human blood and placenta. NPs, with a diameter of less than 1 µm, raise concerns about unknown effects on human health due to their tiny size, and knowledge about their biological effects is limited. To understand the toxicity of MPs and NPs, it is necessary to conduct kinetic and hazard analyses using particles with diverse physical properties. In this study, we focused on polyethylene (PE), which is difficult to obtain nano-sized particles and tried to prepared fluorescent labeled PE (nPE) for dynamics analysis. First, green fluorescent nPE was prepared using Qdot, which enables not only fluorescence observation but also quantitative evaluation by measuring the contained zinc. Following a previous study, PE was dissolved in xylene and dropped into DMSO containing Qdots and warmed to 110-115°C to form particles, and then nPE were collected by filtering. The prepared nPE particles smaller than 1 µm were observed by SEM. Fluorescence microscopy also revealed fluorescence signals from nPE. In the future, we will obtain information on the physical properties and attempt to evaluate their kinetics in vitro and in vivo. Furthermore, we aim to clarify the biological effects of NPs in the environment by preparing NPs made of different polymer types and degraded NPs that mimic NPs in the environment.