Archive for the ‘Centrifuge’ Category

Ceiling fan centrifuge.

March 11, 2012

I needed to pellet a saline solution containing cheek cells for genomic DNA isolation but I did not have a centrifuge that could hold 50mL tubes.  The solution was to tie the centrifuge tube to my ceiling fan with shoestring.  The ceiling fan centrifuge was ghetto, scary-looking, and effective (it had 3 different speed settings!).  I made a video, check it out below.

Before using the fan I first tried to spin the shoelace (with tube) by hand – but this did not work out at all as the solution kept getting stirred.






DIY centrifuges, used centrifuges, and a fun experiment.

September 3, 2011

The background that led to the experiment

I had been thinking about building a centrifuge out of a blender but first I decided to research what other people had done before I tried my own hand at it.  I ran across a number of designs which included  “Dremmelfuge“” and a handheld centrifuge which will eventually damage something.  The best of centrifuges was one that used mixing bowls and a blender.

My own thought was to attach the caps of dry-erase board markers to a blender rotor using wire and gorilla glue.  In my design I wanted to use the blender pitcher as a safety vessel for in the likely event something went flying – but this provided a lot of design challenges.  Ultimately I decided that my idea was bad and most of the other designs were too risky.  If I were to ever revisit centrifuge construction definitely would make a variant of the blender which used mixing bowls.

All of this ended with me surfing eBay and discovering it was not too expensive to just buy a used centrifuge (from $100-150) – which I did.  I manged to find the centrifuge depicted below.  I find the aesthetic design to be quite pleasing and it is a bit sad that this style is not used anymore.  Now that I have a centrifuge, it is time to use it (see below for more)!

My little buddy. Cheap and effective.

A quick centrifuge explanation

Centrifuges spin samples around extremely fast (often >10,000 RPM).  Doing so causes centripetal force to be exerted upon the samples.  In the case of my centrifuge, it spins fast enough for the samples to have the force of 13000 times earths gravity exerted upon them.


What happens when ketchup, milk, sriracha sauce, and russian salad dressing are exposed to 13,000 x earth gravity for 30 minutes?


The source material precentrifugation.

Here are the specimens, precentrifugation.  From left to right we have non-fat milk (Trade Joe’s), Ketchup (Heinz), Sriracha Sauce (Huy Fong Foods) and Russian Saland Dressing (Wish Bone).

First we load the machine…

Rotor with tubes.

Next we run the machine for 30 minutes and we get….

sriracha sauce 13000 x g 30min

Separated out kind of like blood  (serum on top, cells on the bottom).  I would guess that the bottom layer is chili pepper fragments.

russian salad dressing 13000g 30min

This salad dressing has A LOT of ingredients and I will even try to guess as to which layer is what.

nonfat milk 13000g 30min

Milk proteins should be what has collected at the bottom.

heinz ketchup 13000g 30min

The ketchup surprisingly did not separate into layers.

My take home message from this experience was that sometimes the effort and danger in building something myself may not be worth it when one considers the cost and value of used equipment.

PCR Tube Centrifuge

May 29, 2011

A salad spinner, two empty pipette-tip boxes, and tape can be used as an improvised PCR tube centrifuge.

Below is a video of the amalgam in action.

Tape two pipette boxes to the inside of the salad spinner. Take care to balance the whole thing with the boxes (only one is shown in the picture above).

The salad spinners are cheap, amazon has one listed for around 25 bucks.