A method of producing a novel small-scale flow channel in a mesoscale analytic device from a solid multi-layered heterostructure with one or more channel layers sandwiched between adjoining barrier layers. The channel layer consists of a thin-film of a material of different composition than the barrier layers. At least one of the layers has a defined small-scale thickness. A channel or recess is formed in the heterostructure by etching away the channel layer to a preselected depth. The amount of the channel layer which is etched away determines the depth of the channel, and the thickness of the channel layer determines the width. A method of producing a die for forming a small-scale channel is also disclosed.
 This invention was made with government support under Contract No. DE-AC05-00OR22725 awarded by the United States Department of Energy to UT-Battelle, LLC. The government has certain rights in this invention.