Microfluidic platform for label-free viability cell sorting*

Cell biomechanical properties often change in predictable ways with important cell phenotypes changes, such as cell loss of viability. We propose a biophysical approach for cell viability sensing, enumeration, and purification that is label-free and continuous. Using microfluidics, we show that we can separate viable cells from nonviable cells based on the difference in their stiffness with an enrichment factor of >5 and an overall recovery of 95%. The technology consists of a microchannel with diagonal ridges that direct cells along different paths in a manner dependent on cell biomechanical properties. As a result, the sorted viable and nonviable cells are collected at different microchannel outlets. To investigate the sorting process, we use a tracking algorithm that tracks cells moving through the microchannel. Sorting outcomes are correlated with the tracking metrics such as the cell deflection per ridge and the interaction time with ridges in the channel. The approach can be used for cell characterization and purification either in-line with cell bioreactors or after cell manufacture and prior to administration to improve outcomes.