This research involves the detailed study and design of several microfluidic unit operations that combined together, passively deliver analyte to a local, evanescent array coupled (LEAC) sensor. Specifically, this dissertation is focused on minimally instrumented mixing, pumping, and heterogeneous reaction strategies regarding fluids confined to microchannels whose widths and heights are less than 100 microns. These microfluidic platforms present many advantages over their traditional macroscale counterparts, including reduced sample volumes, analysis times, costs, and overall device size. The minimally instrumented unit operations studied in this dissertation work such that no external control is required and power inputs are small enough to be handled by small battery systems. When combined with the LEAC sensor, the unit operations within this dissertation will provide a unique device able to detect a wide variety of biological markers or small molecules with a high degree of portability.