Evaluation of in vivo biodistribution using fluorescent probe labeled microplastic

다국어 초록 (Multilingual Abstract)

Recent studies have shown that microplastics contaminate our food chain and accumulate in the intestines, liver, kidney, muscles, and more. Among them, polyethylene (PE) accounts for a large proportion of microplastics found in domestic fish and shellfish. It is necessary to study for the organs where the plastics were accumulated, and whether it affects the organism by inducing various responses such as oxidative stress. Therefore, form a part of this purpose, the study is performed to observe and evaluate the microplastic accumulation in organs by in vivo fluorescence imaging. We investigated the biodistribution analysis of microplastic particles by using PEs to classify two particle sizes (5μm, 50μm). For fluorescence imaging, PEs were labeled with cyanine5.5 carboxylic acid (Cy5.5), a near-infrared fluorescent dye. The labeled PEs were characterized by DLS, TGA/DSC, and in vitro IVIS spectrum CT (Perkin elmer, USA). To in vivo biodistribution imaging, each of labeled PEs was administered to ICR mice (n=5) as tracking markers, and the images were obtained by using IVIS spectrum CT (excitation 675 nm/emission 720 nm) at each time points. Mean fluorescence intensity graphs were analyzed by region of interests (ROI) that showed the Cy5.5 labeled PEs were gradually released through the stomach over 24 h after administration. In addition to in vivo imaging and ex vivo imaging were also performed after 24 h imaging, and the fluorescence of each organs were observed. However, there was no difference in organ distribution or secretion depending on the size of microplastics and the sex of mice. In this study, the in vivo biodistribution of the Cy5.5 labeled PEs were realized by fluorescent imaging using signal intensity profiles. In future studies, various microplastics and fluorescent probes would be utilized for comparison purpose.