Feedback Control of Microflows

This chapter gives an overview of methods we have developed and experimental results we have achieved for precision feedback control of flows and objects inside microfluidic systems. Essentially, we are doing flow control, but flow control on the microscale, and further even to nanoscale accuracy, to precisely and robustly manipulate liquid packets, particles (e.g., cells and quantum dots), and micro- and nanoobjects (e.g., nanowires). Target applications include methods to miniaturize the operations of a biological laboratory (lab-on-a-chip), e.g., presenting pathogens to on-chip sensing cells or extracting cells from messy biosamples such as saliva, urine, or blood; as well as nonbiological applications such as deterministically placing quantum dots on photonic crystals to make multidot quantum information systems.