Geometry effects on blood separation rate on a rotating disc

The plasma separation rate is enhanced significantly, as much as 8 times faster for whole blood, by simple change of the channel geometry in a rotating disc. It was enhanced in the channels with narrower channel widths and larger tilt angles with respect to the radial direction but independent of the channel depth or spin direction. A modified Ponder-Nakamura-Kuroda (PNK) theory could nicely fit all of the experimental data to a linear line, which data were obtained from spinning discs with various channel designs and blood samples with broad hematocrit range. To the best of our knowledge, this is the first investigation of geometry effects on the particle separation rate on a rotating disc and it will potentially contribute to the further performance enhancement of centrifugal microfluidic devices.