Abstract: Example implementations include a method of manufacturing a biochemical sensor by forming a fluid region in a microfluidic layer, forming a reference electrode on a planar surface of an electrode layer, forming a biochemical sensor electrode on the planar surface, forming a selective membrane on the biochemical sensor electrode, forming an enzymatic material including a biochemical sensing material on the selective membrane, and bonding the electrode layer to the microfluidic layer. Example implementations also include a device with a reference electrode disposed on a planar surface of an electrode layer, a biochemical sensor electrode disposed on the planar surface, a selective membrane disposed on the biochemical sensor electrode and impermeable to at least one biochemical interferent, and an enzymatic layer disposed on the selective membrane and electrically responsive to a biochemical.