I'm trying to collect milk from our knockout mice (at the end of the lactation stage) to isolate milk exosomes. But I have a hard time with milk collection from mice. I have used either pump or needles but with both methods the milk amount is too little (50-100 ul). Is there a way to isolate the milk exosome from whole mammary gland tissue samples ? If yes, how to distinguish between milk derived exosomes from other cellular and extracellular exosome? Any specific markers ?I appreciate your suggestions.