White Blood Cell Separation and Blood Typing Using a Spiral Microdevice

Our immune system is shielded from various pathogens by white blood cells (WBCs), which work as soldiers. WBCs reach the infectious site and kill the invading pathogens. The assessment of WBC activity and function is important in various diseases such as cancer, HIV, and autoimmune disorders; hence their separation is essential. The present study describes a method for WBC separation using the inertial microfluidic technique. A simple spiral microfluidic device with one inlet and three outlets is constructed here for WBC separation. The device functions on a diluted blood sample. Only 2 finger-pricked droplets of blood (~20 µl) are required to prepare the minute volume of a diluted blood sample. A syringe pump is used to infuse the sample into the channel reservoir. The microdevice takes less than 22 s for WBC separation. We report WBC separation efficiency of nearly 90% with 92% RBC rejection ratio. In addition to WBC separation, the spiral microdevice is capable of blood group testing.