文摘
We have developed a novel biosensor for the rapid determination of double-strand (ds) DNA based on the photoinduced electron transfer (PET) from glutathione (GSH) capped CdTe quantum dots (QDs) to praseodymium(III)-rutin (Pr3+-rutin) complex. The biosensor was based on a fluorescence ¡°OFF-ON¡± mode. To provide the platform for dsDNA detection, the Pr3+-rutin complex was first employed as an effective fluorescence quencher to QDs through PET. Because of its strong binding af?nity with Pr3+-rutin complex, dsDNA can break up the low fluoresced ionic ensemble, set free the luminescent QDs. Thus, the recognition of dsDNA by Pr3+-rutin complex can be realized through the restoration of QDs fluorescence. The relative recovered fluorescence intensity is directly proportional to the concentration of herring sperm (hs) DNA between 0.0874 ¦Ìg mL?1 and 20 ¦Ìg mL?1, and the detection limit (3¦Ä/K) is 0.0262 ¦Ìg mL?1. The entire experimental process does not require any chemical modification and coupling of CdTe QDs and dsDNA, greatly simplifying the experimental process. Some possible reaction mechanisms are discussed.