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

Abstract

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.

Fabrication Flexible and Luminescent Nanofibrillated Cellulose Films with Modified SrAl2O4: Eu, Dy Phosphors via Nanoscale Silica and Aminosilane

“…This was probably due to the variations in the local microenvironment including the nano-sized effect of nanofibrillated cellulose and the introduction of moisture during the preparation of films. Despite the occurrence of a slight blue shift for the luminescent films [43,44,45], the luminous color still belongs to green (Figure 5c). The XRD pattern of ONFC luminescent films (Figure 5d) shows the diffraction peaks for both the crystalline ONFC (2θ = 16.5° and 22.5°) and SrAl 2 O 4 , which further confirmed that the SiO 2 and SiO 2 @APTMS modification effectively restrains the hydrolysis of SAOED phosphors.…”

Synthesis of molecularly imprinted dye‐silica nanocomposites with high selectivity and sensitivity: Fluorescent imprinted sensor for rapid and efficient detection of τ‐fluvalinate in vodka

“…Modification of the SiO 2 surface was synthesized as previously reported methods in the literature . In a typical procedure, SiO 2 nanoparticles (200 mg) were dispersed in the ethanol (60 mL) after ultrasonication for 1 h, and then MPTMS (2 mL) was added and stirred at 40°C for 24 h. After the modification, SiO 2 ‐MPTMS nanoparticles were obtained by centrifugation and vacuum drying at 60°C for 12 h.…”

Gold Nanoparticle-Quantum Dot Fluorescent Nanohybrid: Application for Localized Surface Plasmon Resonance-induced Molecular Beacon Ultrasensitive DNA Detection

“…SiO 2 -capped CdZnSeS/ZnSe 1.0 S 1.3 Qdots were prepared by silanization [22, 23] of TGA-capped alloyed CdZnSeS/ZnSe 1.0 S 1.3 Qdots. The synthesis of alloyed TGA-capped CdZnSeS/ZnSe 1.0 S 1.3 Qdots has been reported by our group [20].…”