Silica-coated gold nanorod@CdSeTe ternary quantum dots core/shell structure for fluorescence detection and dual-modal imaging

Abstract

Abstract The applications based on ternary quantum dots (QDs) in biosensor have attracted wide interest due to their unique optical properties. It makes sense to construct a comprehensive optical biologic probe with fluorophores and plasmonic functional groups in precise co-localized bio-imaging probe development. Herein, we fabricated a novel hierarchical Au nanorod (NR)@CdSeTe quantum dots core/shell structure using silicon isolation layer for biological application. AuNRs were mediated by an initial mesoporous silica layer and coated with a dense layer of silica, and then CdSeTe QDs were directly assembled on the surface. The dense silica layer can reduce the potential fluorescence resonance energy transfer (FRET) between QDs and AuNRs. The molecular beacon (MB)-conjugated AuNR@CdSeTe fluorescent biosensors were prepared by nucleic acid hybridization technology in order to overcome the limitations of conventional probes for Norovirus (NV). The MB-conjugated AuNR@CdSeTe bioprobes have a good performance in the linearity, and the linear range of this assay is from 2 to 18 copies/mL with a limit of detection (LOD) of 1.2 copies/mL. In addition, PEGylated AuNR@CdSeTe-SiO2 nanoparticles have implemented in a dual-modal imaging with high contrasting fluorescence and dark field signals in cell imaging, which has a great potential in cancer diagnosis.