Porous Silicon Waveguides for Small Molecule Detection

A porous silicon resonant waveguide biosensor is demonstrated for the selective detection of DNA and other small molecules. Due to the large surface area of porous silicon and the enhanced interaction of target molecules with the electric field in the waveguide, porous silicon waveguides serve as the basis for efficient biosensing devices. In contrast to traditional evanescent wave sensors for which biomolecules are exposed to an exponentially decaying field, in the porous silicon waveguide sensor, biomolecules are infiltrated directly into the core of the waveguide where the electric field is most strongly concentrated. Experimental demonstrations of the selective detection of complimentary DNA oligos, with negligible response for both non-complementary DNA and buffer controls, have been performed.