ViaChip for Size-based Enrichment of Viable Cells.

Live cells acquire different fates including apoptosis, necrosis, and senescence in response to stress and stimuli. Rapid and label-free enrichment of live cells from a mixture of cells adopting various cell fates remains a challenge. We developed a ViaChip for high-throughput enrichment of Viable cells via size-based separation on a multi-stage microfluidic Chip. Our chip takes advantage of the characteristic increase in cell size during cellular senescence and decreases during apoptosis and necrosis, in comparison to their viable and healthy counterparts. The core component of our ViaChip is a slanted and tunable 3D filter array in the vertical direction (z-gap) for rapid and continuous cell sieving. The shape of the 3D filter array is optimized for target cells to prevent clogging during continuous separation. We demonstrated enrichment of live human and mouse mesenchymal stem cells in culture and from live animals, as well as the removal of senescent and necrotic MSCs, respectively, achieving an enrichment efficiency of ~67% with the continuous flow at 1.5 mL/hour. With further improvements in throughput and separation efficiency, our ViaChip could find applications in cell-based drug screening for anti-cancer and anti-aging cell therapies.