A method comprising the steps of: (a) providing a microfluidic device comprising a substrate and one or more microchannels formed therein; (b) introducing a stream of aqueous fluid into an inlet of a microchannel of the microfluidic device and flowing, in response to application of a pressure, the stream of aqueous fluid through the microchannel downstream towards an outlet of the microchannel, wherein the aqueous fluid contains a mixture of at least one biological molecule, one or more reagents for conducting a reaction with the at least one biological molecule, and multiple detectable markers; (c) providing a carrier fluid within the substrate and at the outlet of the microchannel, wherein the carrier fluid is immiscible with the aqueous fluid; (d) forming a plurality of plugs of the aqueous fluid in the carrier fluid based, at least in part, on the flow of the stream of aqueous fluid and surface tension of the aqueous fluid relative to the carrier fluid at the outlet of the microchannel, wherein at least a first plug and a second plug each comprise the at least one biological molecule, the one or more reagents for conducting a reaction with the at least one biological molecule, and the multiple detectable markers, and each are substantially surrounded by the carrier fluid, and wherein: (i) the first plug includes a marker identifying a characteristic of the first plug upon producing a detectable signal in response to said reaction; and (ii) the second plug includes a marker identifying a characteristic of the second plug upon producing a detectable signal in response to said reaction. (a) providing a microfluidic device comprising a substrate and one or more microchannels formed therein; (b) introducing a stream of aqueous fluid into an inlet of a microchannel of the microfluidic device and flowing, in response to application of a pressure, the stream of aqueous fluid through the microchannel downstream towards an outlet of the microchannel, wherein the aqueous fluid contains a mixture of at least one biological molecule, one or more reagents for conducting a reaction with the at least one biological molecule, and multiple detectable markers; (c) providing a carrier fluid within the substrate and at the outlet of the microchannel, wherein the carrier fluid is immiscible with the aqueous fluid; (d) forming a plurality of plugs of the aqueous fluid in the carrier fluid based, at least in part, on the flow of the stream of aqueous fluid and surface tension of the aqueous fluid relative to the carrier fluid at the outlet of the microchannel, wherein at least a first plug and a second plug each comprise the at least one biological molecule, the one or more reagents for conducting a reaction with the at least one biological molecule, and the multiple detectable markers, and each are substantially surrounded by the carrier fluid, and wherein: (i) the first plug includes a marker identifying a characteristic of the first plug upon producing a detectable signal in response to said reaction; and (ii) the second plug includes a marker identifying a characteristic of the second plug upon producing a detectable signal in response to said reaction. (i) the first plug includes a marker identifying a characteristic of the first plug upon producing a detectable signal in response to said reaction; and (ii) the second plug includes a marker identifying a characteristic of the second plug upon producing a detectable signal in response to said reaction.