The Squires group develops microfluidic “labs on chips” that probe fundamental phenomena coupling physical, chemical, and fluid-mechanical processes.  Specific areas including probing the migration of suspended colloids, drops and polymers under chemical gradients of various types, and the conceptual design of systems that exploit such migration, e.g. to drive engineered particles to ‘find’ regions of interest. Additionally, new label-free techniques enable chemical concentration fields to be visualized as they evolve, opening new windows to directly track multicomponent transport.