You need more exosomes for RNA. You need to focus experiment on the RNA isolation, as it can be much more easily degraded in handling than proteins. 1 ml of serum should be sufficient, but since having trouble scale up and use more. A 10 ml red top tube blood sample tube from patients will give you 4 to 5 ml of serum, and is not too much to take from a patient. Patient samples may or may not secrete more exosomes, although I would expect more. Isolate total RNA from the exosomes after rupturing, and purify this using standard RNA isolation methods. Send for sequencing at a reliable facility. You might want to check with others at your institution where they send their RNA samples for analysis, as a poor job processing and sequencing your sample can ruin a good sample.

Thank you for your suggestion Dr. Knowlton. Since I am using archival serum samples, I have an access only for 1.2 ml of patient sample. I tried using the miRCURY kit for isolation of total RNA, preserving miRNA, and my sample shows a huge peak at 230 nm on nanodrop, indicating a possibility of salt contamination. Is there a way to resolve this? The protocol recommends adding elution buffer in the last step. Would substitution with RNAse free water help solve the problem?

Dear Sneha,

The Nanodrop might be the problem here as it is very unreliable in quantifying