DNA adsorption by magnetic iron oxide nanoparticles and its application for arsenate detection

Iron oxide nanoparticles adsorb fluorescently labeled DNA oligonucleotides via the backbone phosphate and quench fluorescence. Arsenate displaces adsorbed DNA to increase fluorescence, allowing detection of arsenate down to 300 nM. This is a new way of using DNA: analyte recognition relies on its phosphate instead of the bases.