Will It Centrifuge? (part 2 - Blood!)





Introduction: Will It Centrifuge? (part 2 - Blood!)

About: The answer is lasers, now, what was the question? If you need help, feel free to contact me. Find me on Reddit, Tumblr and Twitter as @KitemanX

Yes, blood!

Only a slide-show again, because I was just taking an opportunity that came up.

A colleague at school did a lamb's-heart dissection, so I grabbed a few millilitres of the blood and centrifuged it at 8,500g for five minutes.

I did not get the results I expected (see the slideshow). I was blaming it on the blood being at least two days old before I got to it, and not kept cool enough in that time, but I have since found out that blood is usually centrifuged for at least half an hour.




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    36 Discussions

    how about if i centrifugate a mixture of mammalian blood and distilled water for studying osmosis? thanks a lot

    1 reply

    You can try - have a read of the other comments on this instructable, they're from people that actually know what they're talking about.

    Hi, I think you'll find that you're spinning the blood too fast. What happens is the blood cells haemolize and break down leaving you with a lot of liquid tainted with red heme molecules. Next time go 3500rpm for 10 min, thats what we do at the lab where I work.

    4 replies


    Thank you!

    That's one of the things I love about this site - somewhere there's an expert on everything.

    I'm part-way through a "how to centrifuge" ible - could you PM me any useful links? Or advice?

    Cool, I never noticed this instructable before. In our lab, we use 1200rpm for 10min. However we need to be gentle with our cells, we want them alive, since we culture them. At this rpm, you will see a layer of red cells, white cells, and serum. Occasionally, we even see an fat layer floating on top. If the blood is old, you'll likely see a clot, sodium heparin in the collection tubes prevent clotting.

    Any rough handling breaks some cells. If I recall correctly when you centrifuge cells without an anticoagulant you can't centrifuge the buffy coat, or white Blood cells, visible, they are mixed in the clot. So you either need a test-tube with an anticoagulant (heparin, EDTA or something) or need to add it when drawing the blood. My experiences are from a commercial blood lab where kits are used when possible so amounts of anticoagulant is a mystery to me, it just said 'vacutainer EDTA' on the tubes :).
    I tried to look for a method to separate the parts but my source did not tell (qiagen DNA extraction kit manual). Anyway, the rpm doesn't say how much it is in g's, so be careful when spinning.

    Got a question. I design scientific and medical instruments. In your opinion how do you think blood in urine would settle out in your expected results? Would it mix with the plasma at the top or would it separate from the plasma? I know I should test these things out, just looking for your thoughts. Thanks ejoe

    1 reply

    My thoughts are that the cells and platelets would settle out, but the plasma and urine would remain in a fairly homogeneous mixture above. I also think that, if you're designing a test for blood in urine samples, the existing dip-strips are probably more sensitive, quicker and less of a biohazard.

    Awww... now I want some BLOOD! *licks lips in a very hungry (or thirsty in this case) way*

    They spin samples really fast to make their component parts settle out. Here, I was attempting to make all the cells in the blood settle to the bottom and leave relatively-clear plasma on the top.

    You know how you can keep the water in a bucket when you spin it over your head?

    You're putting a force of just over 1 gravity on the water.

    Now imagine a machine that spins sample 13,000 times a minute, that's a centrifuge.

    These sideshows have inspired me to make a centrifuge, because its a lot more fun to make one than to buy one. if only i had some proper machine tools.

    Hey, Kiteman. Where could one get a centrifuge for pretty cheap? I saw one online that was 159.99 and it looked pretty decent, but I wouldn't know what one would need to do some tests like this; like g-force wise or size wise. I think the ones I would want would be Small Medical ones. But then again, I have no clue what I need. Then there's the obvious question of whether or not someone could DIY one. Let me know what you think.

    1 reply

    Kiteman, do peanut butter, oh actually it would be interesting to try a few different butters and margarines, see which really has the least oily stuff in it...