A microfluidically-controlled transmission mode nanoscal surface plasmonics sensor device comprises one or more arrays of aligned nanochannels in fluid communication with inflowing and outflowing fluid handling manifolds that control the flow of fluid through the array(s). Fluid comprising a sample for analysis is moved from an inlet manifold, through the nanochannel array, and out through an exit manifold. The fluid may also contain a reagent used to modify the interior surfaces of the nanochannels, and/or a reagent required for the detection of an analyte.