摘要
The ability to present cells with stimuli that vary in space and time is key for a mechanistic understanding of dynamic processes such as cell migration, growth, adaptation, and differentiation. Microfluidic gradient devices that output multiple concentrations of a given compound exist, but changing the output generally requires a change in flow rates that can be confounding in biological measurements and/or impractical for high-throughput applications. We present chaotic mixers that generate multiple, complex concentration gradients that can be smoothly varied in time without significantly altering the flow rate. © 2006 American Institute of Physics.