Efficient Mixing and Reactions within Microfluidic Channels Using Microbead-Supported Catalysts

A strategy for efficiently mixing solutions and carrying out multistep catalytic reactions in microfluidic systems is described. The approach involves immobilizing catalysts on microbeads, placing the beads into well-defined microreactor zones, and then passing reactants through one or more of the reactor zones to yield products. The catalyst-modified beads effectively mix reactants and increase the effective surface area of the channel interior, both of which improve reaction velocities compared to open channels. This approach is demonstrated using two sequential reactions catalyzed by glucose oxidase and horseradish peroxidase. In addition to providing a general route to chemical synthesis within microfluidic systems, this design strategy may also be applicable to modeling reaction pathways within cells and to bio/chemical sensing applications.