Device puts cells in the flow

Studying how chemicals affect cells requires precise control of the doses they receive. A new device designed by graduate student Rex Nielson and chemistry professor Jason B. Shear at the University of Texas, Austin, allows them to dose multiple cellular targets in parallel (Anal. Chem., DOI: 10.1021/ac061084i). Their method relies on a simple microfluidic device that consists of a pair of stacked flow chambers, one holding the cell culture and the other serving as a reagent flow cell. The cultured cells are grown on a membrane that is inserted as a barrier between the two chambers. With a pulsed laser, Nielson and Shear drill micrometer-scale holes in the membrane, allowing plumes of reagent to flow from the reagent chamber into the cell-culture chamber and wash over the selected cells or subcellular regions. The reagent streams can be turned off by plugging the holes with photo-cross-linked proteins. Shear and Nielson are starting to use the device to study how multiple neurons in a network respond to chemical stimulation.