Effect of DNA-induced corrosion on passivated porous silicon biosensors.

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.

Semitransparent nanostructured films for imaging mass spectrometry and optical microscopy.

Semitransparent porous silicon substrates have been developed for pairing nanostructure-initiator mass spectrometry (NIMS) imaging with traditional optical-based microscopy techniques. Substrates were optimized to generate the largest NIMS signal while maintaining sufficient transparency to allow visible light to pass through for optical microscopy. Using these substrates, both phase-contrast and NIMS images of phospholipids from a scratch-wounded cell monolayer were obtained.