Characterizing osmotic lysis kinetics under microfluidic hydrodynamic focusing for erythrocyte fragility studies

The biomechanics of erythrocytes, determined by the membrane integrity and cytoskeletal structure, provides critical information on diseases such as diabetes mellitus, myocardial infarction, hypertension, and sickle cell anemia. Here we demonstrate a simple microfluidic tool for examining erythrocyte fragility based on characterizing osmotic lysis kinetics. Hydrodynamic focusing is used for generating rapid dilution of the buffer and producing lysis of erythrocytes during their flow. The lysis kinetics are tracked by monitoring the release of intracellular contents from cells via recording the light intensity of erythrocytes at various locations in the channel. Such release profile reflects sensitively the changes in erythrocyte fragility induced by chemical, heating, and glucose treatment. Our tool provides a simple approach for probing red blood cell fragility in both basic research and clinical settings.