A system for isolating and emulsifying particles or cells within droplets includes a microfluidic trapping device having an inlet and an outlet and one or more channels disposed between the inlet and the outlet, at least some of the one or more channels having a plurality of expansion regions serially arranged along the length thereof. A droplet generation device is fluidically coupled to the outlet of the microfluidic trapping device, the droplet generation device has a plurality of channels of a first height that terminate at an interface into a chamber having a second height that is greater than the first height, wherein the plurality of channels droplet generation device and the chamber contain an oil phase therein and wherein the interface is a step junction. In some embodiments, the droplet generation device is itself oriented at an angle with respect to horizontal to prevent droplet coalescence.