Materials Research Project
The detection of trace amounts of pathogens, such as anthrax, is typically complicated by the low signal to noise ratio of detection schemes. In this project, we are addressing this problem by fabricating micro-scale retroreflecting elements, which can be detected with high sensitivity.
These elements act as mirrors, which, over a broad angle, return light directly toward its source and, in such, are extremely detectable. In fact, a set of corner-cube retroreflectors on the lunar surface is routinely detected and ranged as part of ongoing experiments on lunar orbital dynamics.
In one implementation, the cornercubes are coated with probe material so that the pathogen(i.e., anthrax) DNA acts as glue that bonds the retroreflector to a known surface. In another approach, pathogen DNA acts as a glue that binds components of retroreflectors together so that they self-assemble.
The retroreflectors are fabricated using standard semiconductor processing approaches; several billion elements can be manufactured simultaneously on a single substrate. The image to the left is a scanning electron micrograph of the surface of such wafer. The square shapes will be etched into the underlying surface to form the cubes.