Heba Kamal Nabih Hanafi We incubate exosomes with the PKH67 fluorescent dye in ratio of 100 ul exosomes to 0.5 ul dye for 5 to 10 mins at RT. After that remember to clean up the dye using https://www.thermofisher.com/order/catalog/product/4484449?us&en#/4484449?us&en to remove free dyes are present in the mixture. Best.

In our study, exosomes were labeled with PKH67 dye (Sigma-Aldrich, Missouri, USA) in the dark and blocked with FBS. 2 µl PKH67 dye was added to 100 μg of exosomes and 5 min incubation was done. Then, the reaction was blocked with exosome-free FBS. To remove unincorporated labels, exosome isolation was carried out

https://pubmed.ncbi.nlm.nih.gov/32891471/

(@Surya Srivastava)

Thank you so much for your recommended spin columns to get rid of the excess dye. Could you please, recommend also the appropriate concentration or volume of exosomes that will be co-cultured with about 300,000 cells in 6-well plate?..Thanks in advance.

@Mohammad Mahmoudi

Thank you so much for your appreciated reply.