A quantitative study of nanoplastics within cells using magnetic resonance imaging

Concerns regarding the environmental hazards and health risks of nanoplastics (NPs) are increasing. However, quantifying of NPs in vivo remains challenging. In this study, we propose a strategy for using magnetic resonance imaging (MRI) to quantify NPs internalized by mouse macrophages. Model NPs (Fe₃O₄@PS) with more homogeneous sizes and morphologies were obtained by encapsulating Fe₃O₄ in polystyrene. A standard curve was generated by linearly fitting the intensity and concentration charts to the Fe₃O₄@PS MRI data. The mass of Fe₃O₄@PS captured by the mouse macrophages was estimated using a standard curve. An explanation of how the standard curves were created and used is provided in the text. The accuracy of the MRI results was demonstrated using, inductively coupled plasma (ICP). Quantitative results from MRI and ICP revealed that the mouse macrophage uptake increased as NPs concentrations decreased. According to the ICP results, when the NPs exposure concentration was 10 μg/mL, the uptake rate by mouse macrophages was 63.0 %. The quantitative MRI results were slightly lower than those for ICP, with an uptake rate of 57.7 % in mouse macrophages at the same concentration. Therefore, MRI provides a new perspective for quantitative NPs analysis.