Volume 9, Issue 7 2401996
Research Article

Glycan-Anchored Fluorescence Labeling of Milk-Derived Extracellular Vesicles for Investigating Their Cellular Uptake and Intracellular Fate

Xueqi Su

Xueqi Su

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Siqin Zhang

Siqin Zhang

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Tianyu Zhang

Tianyu Zhang

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Xueping Pan

Xueping Pan

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Yingying Ke

Yingying Ke

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Yalan Fan

Yalan Fan

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Jian Li

Jian Li

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Lingyu Zhang

Lingyu Zhang

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

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Chaoxiang Chen

Corresponding Author

Chaoxiang Chen

College of Ocean Food and Biological Engineering, Jimei University, Xiamen, Fujian, 361000 China

E-mail: [email protected]

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First published: 25 February 2025

Abstract

Milk-derived extracellular vesicles (mEVs) are promising therapeutic delivery platforms due to their natural bioactivity, biocompatibility, and ability to cross biological barriers. However, analyzing their cellular uptake and trafficking is limited by existing fluorescent labeling methods, which often cause dye leakage and disrupt vesicle integrity. Here, a glycan-anchored fluorescence labeling strategy for mEVs is developed, involving periodate oxidation of surface sialic acids followed by aniline-catalyzed ligation of hydrazide-functionalized fluorophores. Nano-flow cytometry characterization confirmed ≈100% labeling efficiency without compromising mEVs integrity or uptake behavior. This approach enabled quantitative analysis of mEVs internalization, identifying clathrin-mediated endocytosis and macropinocytosis as the primary pathways and confirming mEVs’ capacity for lysosomal escape. Comparative analyses showed that traditional lipophilic dyes induced vesicle aggregation, dye leakage, and transfer, potentially misrepresenting mEVs behavior. Additionally, co-labeling mEVs with glycan-anchored fluorophores and FITC-conjugated paclitaxel enabled real-time tracking of drug delivery, revealing a burst release from lysosomes that led to significant cytotoxicity. Overall, the glycan-anchored fluorescence labeling allows precise analysis of mEVs uptake and intracellular fate, paving the way for further research and application in targeted drug delivery.

Conflict of Interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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