Wide visible-range activatable fluorescence ZnSe:Eu3+/Mn2+@ZnS quantum dots: local atomic structure order and application as a nanoprobe for bioimaging. Issue 2 (8th December 2021)

• Record Type: Journal Article
• Authors: Khan, Zahid Ullah; Uchiyama, Mayara Klimuk; Khan, Latif Ullah; Araki, Koiti; Goto, Hiro; Felinto, Maria Claudia França Cunha; de Souza, Ana Olivia; de Brito, Hermi Felinto; Gidlund, Magnus
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 2(2021)
• Page Start: 247
• Page End: 261
• Publication Date: 2021-12-08
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Biomedical materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1tb01870a
• Languages: English
• ISSNs: 2050-750X

Abstract

Abstract : To develop fluorescent bionanoprobe for cellular imaging, it is crucial to get precise insight on the particle–cell interaction, optical properties of QDs in and out of the cell, their movement in and out of the cell, and the final fate of particle. Abstract : The development of QDs-based fluorescent bionanoprobe for cellular imaging fundamentally relies upon the precise knowledge of particle–cell interaction, optical properties of QDs inside and outside of the cell, movement of a particle in and out of the cell, and the fate of particle. We reported engineering and physicochemical characterization of water-dispersible Eu 3+ /Mn 2+ co-doped ZnSe@ZnS core/shell QDs and studied their potential as a bionanoprobe for biomedical applications, evaluating their biocompatibility, fluorescence behaviour by CytoViva dual mode fluorescence imaging, time-dependent uptake, endocytosis and exocytosis in RAW 264.7 macrophages. The oxidation state and local atomic structure of the Eu dopant studied by X-ray absorption fine structure (XAFS) analysis manifested that the Eu 3+ ions occupied sites in both ZnSe and ZnS lattices for the core/shell QDs. A novel approach was developed to relieve the excitation constraint of wide bandgap ZnSe by co-incorporation of Eu 3+ /Mn 2+ codopants, enabling the QDs to be excited at a wide UV-visible range. The QDs displayed tunable emission colors by a gradual increase in Eu 3+ concentration at a fixed amount of Mn 2+, systematically enhancing the Mn 2+ emission intensity via energy transfer from the Eu 3+ to Mn 2+ ion. The ZnSe:Eu 3+ /Mn 2+ @ZnS QDs presented high cell viability above 85% and induced no cell activation. The detailed analyses of QDs-treated cells by dual mode fluorescence CytoViva microscopy confirmed the systematic color-tunable fluorescence and its intensity enhances as a function of incubation time. The QDs were internalized by the cells predominantly via macropinocytosis and other lipid raft-mediated endocytic pathways, retaining an efficient amount for 24 h. The unique color tunability and consistent high intensity emission make these QDs useful for developing a multiplex fluorescent bionanoprobe, activatable in wide-visible region.