Modelling and prototyping of a microfluidic cartridge for extracting immune cells from small volume blood samples

Within the human blood immune cells assume specific functions to modulate and control the human immune response. Consequently, they are used for the diagnosis and treatment of autoimmune and hematologic diseases. Traceless Affinity Cell Selection Technology (Fab-TACS® technology) is a new method for selective isolation of specific immune cells from blood samples. Currently, the technology is used in a 60 mL syringe-like cartridge, which is operated by a control unit (Fabian®). Nevertheless, diagnostic applications require the reduction of the sample volume to several microliters. Therefore, we developed a cartridge for the purification of small blood volumes with the aid of suitable scaling and simulation methods. By implementing a multi domain physical systems model of the established cartridge we could simulate the separation process. Based on that a microfluidic cartridge was designed and several prototypes were manufactured. To operate the microfluidic cartridge a setup and software for fluidic control were created. Afterwards the prototype cartridge and the microfluidic control were used to isolate lymphocytes from a buffy coat. By flow cytometric analysis we could show that it is possible to isolate lymphocytes with a purity that is comparable to the established 60 mL syringe-like cartridge.