Multiplexed optical detection of plasma porphyrins using DNA aptamer-functionalized carbon nanotubes

A novel optical platform based on DNA aptamer-functionalized SWCNTs (a-SWCNTs) is developed for multiplexed detection of plasma porphyrins. We have investigated the interactions of a-SWCNTs with heme (FePP), protoporphyrin (PP), coproporphyrin (CP), and uroporphyrin (UP). Two interaction mechanisms, specific binding, and nonspecific adsorption between porphyrins and a-SWCNTs are proposed based on observed optical signal modulations. The optical transduction signals are used to formulate a multiplexed detection strategy for the four porphyrin species without a laborious separation process. The detection scheme is sensitive, selective, and can readily be used for porphyrin detection in plasma samples when combined with a solvent extraction method. Our optical platform offers novel analytical tools for probing the surface chemistry at the porphyrin/a-SWCNTs interface, showing great promise for both research and clinical applications.