Cnidarian Microcentrifuge Tube Filter

Often times, the procedure for purifying a biological macromolecule will call for sedimenting unwanted cellular debris through centrifugation. The crap sinks to the bottom, and the supernatant containing the molecule of interest is siphoned off into another tube. Unfortunately, there may be some particulate remnants floating around in the milieu, especially if the sample has some component with a density less than that of water (e.g., oil bodies).

I've observed that these recalcitrant particles tend to stick to a pipette tip should they contact one, so why not make a filter that acts on this principle? A polypropylene tentacle, which plugs into the business end of a micropipette, is inserted into the tube containing the supernatant, spun around a bit to capture the debris in suspension, held above the the tube to drain the solution back into the tube, and disposed of.

The tentacle itself resembles a tassel. The bottom is flayed so that it contacts all of the solution when agitated, but twists when spun in one direction so that the solution is wicked down the tentacle and into the tube.

I think that a gizmo such as this would be preferable to spinning a sample a second time or having to cut out a little bit of cheese cloth, particularly when working with millilitre amounts.