Putting The Squeeze On Cells

A new microfluidic device can rapidly analyze the size and rigidity of cells all at once (Anal. Chem., DOI: 10.1021/ac300264v). Cells are a bit like pillows, ranging from hard to soft. Previous high-throughput methods to measure cell stiffness infer the property from the time it takes a cell to travel through a microfluidic channel: Firm cells take longer to squeeze through tiny passageways than soft cells do. But MIT’s Klavs F. Jensen wanted to build a device that also takes into account cell size to improve stiffness measurements. His team’s device consists of a microfluidic path running between two electrodes. By measuring electrical resistance, the researchers can determine the size of a cell passing through. As cell size increases, so does resistance. They can also measure the cell’s transit time via how long this resistance spike lasts. The researchers tested the device on HeLa cells, some of which they softened with a toxin that breaks down the cytoskeleton. As predicted, softer cells took less travel time than harder, untreated cells, and smaller cells traveled faster than larger cells.