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Published on: November 20, 2013
Effect of DNA-induced corrosion on passivated porous silicon biosensors
Yiliang Zhao1, Jenifer L Lawrie, Kelsey R Beavers
1Interdisciplinary Graduate Program in Materials Science, ‡Department of Chemical and Biomolecular Engineering, and §Department of Electrical Engineering and Computer Science, Vanderbilt University , Nashville, Tennessee 37235, United States.
Abstract:
This work examines the influence of charge density and surface passivation on the DNA-induced corrosion of porous silicon (PSi) waveguides in order to improve PSi biosensor sensitivity, reliability, and reproducibility when exposed to negatively charged DNA molecules. Increasing the concentration of either DNA probes or targets enhances the corrosion process and masks binding events. While passivation of the PSi surface by oxidation and silanization is shown to diminish the corrosion rate and lead to a saturation in the changes by corrosion after about 2 h, complete mitigation can be achieved by replacing the DNA probe molecules with charge-neutral PNA probe molecules. A model to explain the DNA-induced corrosion behavior, consistent with experimental characterization of the PSi through Fourier transform infrared spectroscopy and prism coupling optical measurements, is also introduced.
