An ultrasensitive SiO2-encapsulated alloyed CdZnSeS quantum dot-molecular beacon nanobiosensor for norovirus

Oluwasesan Adegoke, Min-Woong Seo, Tatsuya Kato, Shoji Kawahito, Enoch Y. Park (Lead / Corresponding author)

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37 Citations (Scopus)
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Ultrasensitive, rapid and selective diagnostic probes are urgently needed to overcome the limitations of traditional probes for norovirus (NV). Here, we report the detection of NV genogroup II via nucleic acid hybridization technology using a quantum dot (QD)-conjugated molecular beacon (MB) probe. To boost the sensitivity of the MB assay system, an ultrasensitive QD fluorophore with unique optical properties was synthesized, characterized and exploited as a fluorescence signal generator. Alloyed thioglycolic (TGA)-capped CdZnSeS QDs with a high photoluminescence (PL) quantum yield (QY) value of 92% were synthesized, and a modified silanization method was employed to encapsulate the thiol-capped QDs in a silica layer. The resulting highly luminescent alloyed SiO2-coated CdZnSeS QDs had a remarkable PL QY value of 98%. Transmission electron microscopy and dynamic light scattering confirmed the monodispersity of the alloyed nanocrystals, and zeta potential analysis confirmed their colloidal stability. Powder X-ray diffraction and PL lifetime measurements confirmed the surface modification of the QDs. The alloyed TGA-capped and SiO2-coated CdZnSeS QD-conjugated MB bioprobes detected extremely low concentrations of NV RNA. Ultrasensitive detection of low concentrations of NV RNA with a limit of detection (LOD) of 8.2copies/mL in human serum and a LOD of 9.3 copies/mL in buffer was achieved using the SiO2-coated CdZnSeS QD-MB probes, an increase in sensitivity of 3-fold compared with the detection limit for NV RNA using TGA-capped CdZnSeS QD-MBs. The additional merits of our detection system are rapidity, specificity and improved sensitivity over conventional molecular test probes.

Original languageEnglish
Pages (from-to)135-142
Number of pages8
JournalBiosensors and Bioelectronics
Early online date11 Jun 2016
Publication statusPublished - 15 Dec 2016


  • Biosensing Techniques/instrumentation
  • Cadmium Compounds/chemistry
  • Coated Materials, Biocompatible/chemical synthesis
  • Equipment Design
  • Equipment Failure Analysis
  • Molecular Probe Techniques/instrumentation
  • Molecular Probes/chemical synthesis
  • Nanotechnology/instrumentation
  • Norovirus/isolation & purification
  • Quantum Dots
  • RNA, Viral/blood
  • Reproducibility of Results
  • Selenium Compounds/chemistry
  • Sensitivity and Specificity
  • Silicon/chemistry
  • Silicon Dioxide/chemistry
  • Zinc Compounds/chemistry


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