The present invention provides sensors for use in detecting the presence or absence of analytes, systems incorporating the sensors, and methods for using the sensors. The sensors include thin membranes that undergo a detectable geometry change upon exposure to an analyte. In one exemplary embodiment, the sensors are small, thin-film membranes that include a stained semiconductor bilayer, wherein an interaction between the membrane and an analyte induces a detectable change in a strain-induced curvature of the membrane.