Running 10 um Beads Through 2 um Pore Membrane
It is the goal of the Leukocyte counter to have the cells align to a membrane with a one cell to one pore ratio. Ideally the cells would be able to take up pores without using all the pores on the membrane. A possible way to do this would be to dilute the cells enough that they would be able to find a pore without aggregation on top of the membrane. However, if aggregation did occur the flow of the diluted sample would be able to be “sloshed” in order to roll the cells across the membrane until a vacant pore was found. Since there are restriction on using blood in the lab, and in an attempt to perfect all procedures before the use of blood, Fluospheres Polystyrene beads are being used instead. A dilution test using Flousphere beads to mirror the leukocytes was preformed to try to accomplish the goal of having the beads interact with the membrane in the same way the cells ideally would. 10 um Flousphere Polystyrene Microspheres were diluted into a stock solution of PBS from their original concentration of 3.6*10^6 beads/ml to 9*10^5 beads/ml. This specific concentration was chosen because it mirrors the concentration of leukocytes found in the blood. The beads were further diluted 1/1000 into PBS again. The chip holding the membrane was flushed with PBS and then incubated with BSA. The results showed some examples of bead rolling on the membrane which is promising, but due to bubble presence in the sample the effectiveness of the dilution can not accurately be determined.
http://www.youtube.com/watch?v=ofnJm4clzME&feature=youtu.be
