Interferometric Sensing of Biomolecular Binding Using Nanoporous Aluminum Oxide Templates

We have demonstrated the feasibility of sensing adsorption of untagged molecular analytes in an electrochemically fabricated porous aluminum oxide template with regular nanometer dimension pores by monitoring reflectivity spectra. Combining this with chemistry to functionalize Al2O3 with DNA oligonucleotides, we are able to sense 2 nmol/cm2 of complementary DNA as a 3.4 nm shift in a spectral minimum. We have modeled the change in reflection spectrum versus uptake of analytes to quantify binding. This technique can achieve subpicomole sensitivity in straightforward fashion with 0.1 mm probe spots.