Most sensing sytems are planar; however in some applications such as position or mass detection, 3D sensors that allow an independent read-out along each of the x,y, and z axes facilitate the retreival of directional information. Here we describe a cantilever based probe that is structured in 3D; the probe is mass sensitive and allows independent measurement in each of the x, y, and z axis using optical methods. The probes re self-assembled and can be fabricated en-masse, in a highly parallel manner.