On-chip processing of particles and cells via multilaminar flow streams

The processing of particles, cells, and droplets for reactions, analyses, labeling, and coating is an important aspect of many microfluidic workflows. However, performing multi-step processes is typically a laborious and time-consuming endeavor. By exploiting the laminar nature of flow within microchannels, such procedures can benefit in terms of both speed and simplicity. This can be achieved either by manipulating the flow streams around the objects of interest, particularly for the localized perfusion of cells, or by manipulating the objects themselves within the streams via a range of forces. Here, we review the variety of methods that have been employed for performing such “multilaminar flow” procedures on particles, cells, and droplets.