Purpose: Plastics are used commonly in the world because of its convenience and cost-effectiveness. Microplastics, an environmental threat and human health risk, are widely detected in food, and consequently ingested. However degraded plastics are found everywhere, which cause environmental threat and human health risk. Therefore, real-time monitoring of orally administered microplastics is tremendously important to trace them in the body.

Methods: In this study, to visualize their absorption path, we labeled polystyrene with [⁶⁴Cu]Cu-DOTA. We prepared radiolabeled polystyrene with ⁶⁴Cu after, [⁶⁴Cu]Cu-DOTA-polystyrene was then orally administered to mice and evaluate its transit and absorption in mice using PET imaging. The absorption path and distribution of [⁶⁴Cu]Cu-DOTA-polystyrene were determined using positron emission tomography (PET) over 48 h. Ex vivo tissue-radio thin-layer chromatography (Ex vivo-radioTLC) was used to demonstrate the existence of [⁶⁴Cu]Cu-DOTA-polystyrene in tissue.

Results: PET images demonstrated that [⁶⁴Cu]Cu-DOTA-polystyrene began to transit to the intestine within 1 h. [⁶⁴Cu]Cu-DOTA-polystyrene accumulation in the liver was also observed. Biodistribution of [⁶⁴Cu]Cu-DOTA-polystyrene confirmed the observed distribution of [⁶⁴Cu]Cu-DOTA-polystyrene from PET images. Ex vivo-radioTLC was used to demonstrate that the detected gamma rays originated from [⁶⁴Cu]Cu-DOTA-polystyrene.

Conclusion: This study provided evidence of microplastic accumulation and existence in tissue by using PET imaging, and cross confirmed by ex vivo-radioTLC. The information provided may be used as the basis for future studies on the toxicity of microplastics.