title: Organic-inorganic interface-induced multi-fluorescence of MgO nanocrystal clusters and their applications in cellular imaging.
abstract: Surface functionalization of inorganic nanomaterials through chemical binding of organic ligands on the surface unsaturated atoms, forming unique organic-inorganic interfaces, is a powerful approach for creating special functions for inorganic nanomaterials. Herein, we report the synthesis of hierarchical MgO nanocrystal clusters (NCs) with an organic-inorganic interface induced multi-fluorescence and their application as new alternative labels for cellular imaging. The synthetic method was established by a dissolution and regrowth process with the assistance of carboxylic acid, in which the as-prepared MgO NCs were modified with carboxylic groups at the coordinatively unsaturated atoms of the surface. By introducing acetic acid to partially replace oleic acid in the reaction, the optical absorption of the produced MgO NCs was progressively engineered from the UV to the visible region. Importantly, with wider and continuous absorption profile, those MgO NCs presented bright and tunable multicolor emissions from blue-violet to green and yellow, with the highest absolute quantum yield up to (33±1) %. The overlap for the energy levels of the inorganic-organic interface and low-coordinated states stimulated a unique fluorescence resonance energy transfer phenomenon. Considering the potential application in cellular imaging, such multi-fluorescent MgO NCs were further encapsulated with a silica shell to improve the water solubility and stability. As expected, the as-formed MgO@SiO2 NCs possessed great biocompatibility and high performance in cellular imaging.
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces and department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (P.R. China).
authors.forename: Shuifen
authors.initials: S
authors.lastname: Xie
authors.forename: Shixiong
authors.initials: S
authors.lastname: Bao
authors.forename: Junjie
authors.initials: J
authors.lastname: Ouyang
authors.forename: Xi
authors.initials: X
authors.lastname: Zhou
authors.forename: Qin
authors.initials: Q
authors.lastname: Kuang
authors.forename: Zhaoxiong
authors.initials: Z
authors.lastname: Xie
authors.forename: Lansun
authors.initials: L
authors.lastname: Zheng
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D017895:Manganese Compounds / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D061848:Optical Imaging; D010087:Oxides / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties
chemical_list: D002264:Carboxylic Acids; D005456:Fluorescent Dyes; D017895:Manganese Compounds; D010087:Oxides; C027424:manganese oxide; D012822:Silicon Dioxide
keywords: UV/Vis spectroscopy; carboxylate ligands; fluorescence; imaging agents; magnesium oxide; nanostructures