Specific isolation of exosomes using magnetic nanosphere

Background . Exosomes belong to the class of extracellular vesicles that are secreted by cells and circulate in biological fluids, mediating intercellular communication and signaling in various pathological processes, including modulation of cancer development and tumor microenvironment. Exosomes released by cancer cells at early stages of disease progression expressing specific membrane markers, which makes exosomes a promising biomarker of the disease by liquid biopsy. The main obstacle to the use of exosomes as markers of disease development is the lack of a convenient, inexpensive and rapid method for their isolation and detection. Objective . The aim of this study was to develop a platform for exosome isolation and detection of exosome protein membrane markers. Design and methods . In this work, magnetic nanoparticles functionalized with anti-EpCAM aptamer were developed for selective capture of tumor cell exosomes. The efficiency of magnetic nanoparticles was tested on exosomes derived from EpCAM-positive colon cancer cell line (HT29). To ensure high sensitivity of exosomes from pathologically cells, vesicles were pre-labeled with a lipophilic fluorescent dye (3,3’ dioctadecyloxacarbocyanine). Results . It was shown that magnetic nanoparticles bound with anti-EpCAM aptamer effectively captured exosomes from the HT29 culture medium. The detection limit of about 10 7 exosomes/ml was obtained using flow cytometry method. Conclusion. This study demonstrates an effective method for selective isolation of exosomes from cancer cell, which is promising for diagnostics and monitoring of oncological diseases.