Example sensor apparatus for microfluidic devices and related methods are disclosed. In examples disclosed herein, a method of fabricating a sensor apparatus for a microfluidic device includes etching a portion of an intermediate layer to form a sensor chamber in a substrate assembly, where the substrate assembly has a base layer and the intermediate layer, and where the base layer comprises a first material and the intermediate layer comprises a second material different than the first material. The method includes forming a first electrode and a second electrode in the sensor chamber. The method also includes forming a fluidic transport channel in fluid communication with the sensor chamber, where the fluidic transport channel comprises a third material different than the first material and the second material.