Fluorescent Mn:ZnCdS@ZnS and CdTe Quantum Dots Probeson SiO 2 Microspheres for Versatile Detection of CarcinoembryonicAntigen and Monitoring T4 Polynucleotide Kinase Activity

Versatile fluorescent quantum dots (QDs) probes on SiO2 microspheres were prepared and used for detection of carcinoembryonic antigen (CEA) and monitoring T4 polynucleotide kinase (PNK) activity by integrating with amplification strategy. The highly fluorescent Mn:ZnCdS@ZnS and CdTe QDs showed different emission peaks. The amino-modified SiO2 microspheres with good morphology and no fluorescence interference were designed to link DNA and fabricate multiple branched QDs probes. First, CEA-induced target recycle amplification technique was combined with the Mn:ZnCdS@ZnS QDs labeled P2 signal probe for sensitive detection of CEA. Then, the formed DNA S1–DNA3 double strands further polymerized and proceeded exonuclease-cleavage reaction in the presence of T4 PNK, the released DNA fragments were used to trigger assembly of multibranched CdTe QDs-DNA signal probe (P1) by hybridization chain reaction (HCR), and achieved a greatly amplified fluorescence detection of PNK. The detection limits for CEA and PNK were ...