Diffraction-limited ultrasensitive molecular nano-arrays with singular nano-cone scattering.

Large-library fluorescent molecular arrays remain limited in sensitivity (1 × 10(6) molecules) and dynamic range due to background auto-fluorescence and scattering noise within a large (20-100 μm) fluorescent spot. We report an easily fabricated silica nano-cone array platform, with a detection limit of 100 molecules and a dynamic range that spans 6 decades, due to point (10 nm to 1 μm) illumination of preferentially absorbed tagged targets by singular scattering off wedged cones. Its fluorescent spot reaches diffraction-limited submicron dimensions, which are 10(4) times smaller in area than conventional microarrays, with comparable reduction in detection limit and amplification of dynamic range.