Example 5
Blood plasma comprising lymphocytes and non-target cells was subjected to acoustic energy, generally as described above. Prior to flowing the blood plasma through a microfluidic separation channel, plasma samples were pretreated by diluting with an additive comprising a density gradient medium to provide experimental samples having solution densities ranging between about 1.04 and 1.06 (g/mL) and a control sample having a solution density averaging about 1.08 g/mL. Specifically, the samples were pretreated with Histopaque® media (Sigma-Aldrich, St. Louis, Mo.) to regulate their density.
Surprisingly, the samples having a specific density between about 1.04 and 1.06 g/mL exhibited better purification of lymphocytes. These results were surprising because conventional density medium separation by centrifugation teaches a target density closer to 1.08 g/mL, which is the average density of mononuclear cells. Thus, by regulating the biofluid density to be slightly different than the density of the average target cells (here about 0.02 g/mL to 0.04 g/mL less than the average density of lymphocytes) better purification may be achieved.