Microfluidic cytometer for the characterization of cell lysis.

Blood cytometry and intercellular analysis typically requires lysis as a preparatory step, which can alter the results of downstream analyses. We fabricated a microfluidic cytometer to characterize erythrocyte lysis kinetics. Forward light scatter from erythrocytes was used for enumeration at specific locations on a microfluidic chip. Diffusive transport coupled with laminar flow was used to control the concentration and exposure time of the lysis reagent Zap-OGLOBIN II to erythrocytes. Standard clinical practice is to expose erythrocytes to lysis reagent for 10 min. Under optimum conditions, we achieved complete erythrocyte lysis of a blood sample in 0.7 s. A maximum lysis reaction rate of 1.55 s(-1) was extrapolated from the data. Lysis began after 0.2 s and could be initiated with a lysis reagent concentration of 1.0% (68.5 mM). An equation that related lysis reagent concentration, [A], to erythrocyte lysis, [B], was determined to be [B] = -0.77[A](0.29)t.