Abstract: Microfluidic devices and methods for co-encapsulation of a cell and a controlled release particle in one droplet are escribed herein. The devices and methods utilize laminar flow, high shear liquid-liquid interfaces, hydrodynamic vortices, and/or acoustic focusing to increase co-encapsulation efficiency. The precise variation of the droplets microenvironment is enabled by the controlled release particle co-encapsulated with the single cell in each droplet. This capability, coupled with established detection methods, provides an important tool for precise, single cell analysis.