Chemistrode, a plug-based microfluidic device and method for stimulation and sampling with high temporal, spatial, and chemical resolution

A method for sampling and/or introducing a matter to an environment comprises introducing a first array of plugs through a first microchannel of a device into an exchange region of the device in which mass transport between the environment and the plug fluid of at least one plug in the first array of plugs occurs and a second array of plugs is formed. The exchange region is in fluid communication with the first microchannel. The method further comprises directing the second array of plugs into a second microchannel downstream of and in fluid communication with the exchange region.