Upconversion-luminescent/magnetic dual-functional sub-20 nm core-shell SrF sub(2):Yb,TmaF sub(2):Gd heteronanoparticles

• Published in: Dalton transactions : an international journal of inorganic chemistry 2016-03, Vol.45 (13), p.5800-5807
• Main Authors: Li, Ai-Hua, Lue, Mengyun, Yang, Jun, Chen, Lin, Cui, Xiaohong, Sun, Zhijun
• Format: Article
• Language: English
• Subjects: Dispersions; Illumination; Laser diodes; Magnetic resonance imaging; Medical imaging; Nanostructure; Spectrometers; Upconversion
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c6dt00237d

Sub-20 nm core-shell and water-soluble SrF sub(2):Yb,TmaF sub(2):Gd heteronanoparticles with both upconversion luminescence (UCL) and magnetic resonance imaging (MRI) capabilities were designed and synthesized viaa two-step hydrothermal method. In the design of the heteronanoparticles, SrF sub(2):Yb,Tm nanoparticles with high UCL efficiency are chosen as the core material for strong UCL output; and by epitaxially coating the SrF sub(2):Yb,Tm core particles with inert and biocompatible shells of CaF sub(2):Gd, the core-shell heteronanoparticles are endowed with a magnetic capability (longitudinal relaxivity of 2.4 mM super(-1) s super(-1)) for MRI, as well as an enhancement of the near infrared (NIR) UCL by 9.2 times. The aqueous dispersion of SrF sub(2):Yb,TmaF sub(2):Gd heteronanoparticles with a concentration of 2.6 wt% can emit NIR UCL so as to be easily detected with a fiber optical spectrometer under illumination of a 975 nm laser diode with a power density of 8.8 W cm super(-2). Such a dispersion with a Gd super(3+) concentration of 0.0143 mM in the shell region of the heteronanoparticles can also generate the detectable quickening of longitudinal relaxation. The results promise the strong potential of this nanomaterial for applications in bioimaging as a dual-functional probe.