title: Electron-transfer quenching of nucleic acid-functionalized CdSe/ZnS quantum dots by doxorubicin: a versatile system for the optical detection of DNA, aptamer-substrate complexes and telomerase activity.
abstract: The optical detection of DNA or the sensing of low-molecular-weight substrates or proteins by aptamer nucleic acids is a long term challenge in the design of biosensors. Similarly, the detection of the telomerase activity, a versatile biomarker of cancer cells, is important for rapid cancer diagnostics. We implement the luminescence quenching of the CdSe/ZnS quantum dots (QDs) as a versatile process to develop DNA sensors and aptasensors, and to design an analytical platform for the detection of telomerase activity. The formation of nucleic acid duplexes on QDs, or the assembly of aptamer-substrate complexes on the QDs (substrate=cocaine or thrombin) is accompanied by the intercalation of doxorubicin (DB) into the duplex domains of the resulting recognition complexes. The intercalated DB quenches the luminescence of the QDs, thus leading to the detection readout signal. Similarly, the telomerase-induced formation of the telomere chains on the QDs is followed by the hybridization of nucleic-acid units complementary to the telomere repeat units, and the intercalation of DB into the resulting duplex structure. The resulting luminescence quenching of the QDs provides an indicating signal for the activity of telomerase.
authors.affiliation: Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Sara
authors.initials: S
authors.lastname: Raichlin
authors.forename: Etery
authors.initials: E
authors.lastname: Sharon
authors.forename: Ronit
authors.initials: R
authors.lastname: Freeman
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Tzfati
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D052157:Aptamers, Nucleotide / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry; D045744:Cell Line, Tumor; D003042:Cocaine / Q000032:analysis; D004247:DNA / Q000032:analysis*; D004317:Doxorubicin / Q000737:chemistry*; D004579:Electron Transport; D006801:Humans; D008163:Luminescent Measurements / Q000379:methods; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D019098:Telomerase / Q000378:metabolism*; D013917:Thrombin / Q000032:analysis; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D019187:Cadmium Compounds; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D004317:Doxorubicin; D004247:DNA; C058667:cadmium selenide; D019098:Telomerase; D013917:Thrombin; D003042:Cocaine; C031238:zinc sulfide