Centrifugal microfluidics for sorting immune cells from whole blood.

Sorting and enumeration of immune cells from blood are critical operations involved in many clinical applications. Conventional methods for sorting and counting immune cells from blood, such as flow cytometry and hemocytometers, are tedious, inaccurate, and difficult for implementation for point-of-care (POC) testing. Herein we developed a microscale centrifugal technology termed Centrifugal Microfluidic Chip (CMC) capable of sorting immune cells from blood and in situ cellular analysis in a laboratory setting. Operation of the CMC entailed a blood specimen layered on a density gradient medium and centrifuged in microfluidic channels where immune cell subpopulations could rapidly be sorted into distinct layers according to their density differentials. We systematically studied effects of different blocking molecules for surface passivation of the CMC. We further demonstrated the applicability of CMCs for rapid separation of minimally processed human whole blood without affecting immune cell viability. Multi-color imaging and analysis of immune cell distributions and enrichment such as recovery and purity rates of peripheral blood mononuclear cells (PBMCs) were demonstrated using CMCs. Given its design and operation simplicity, portability, blood cell sorting efficiency, and in situ cellular analysis capability, the CMC holds promise for blood-based diagnosis and disease monitoring in POC applications.