Highly uniform Y3Al2Ga3O12-based nanophosphors for persistent luminescence bioimaging in the visible and NIR regions

In the last few years, persistent phosphors with a garnet crystal structure have attracted a great deal of interest for a plethora of applications ranging from bioimaging to anti-counterfeiting technologies. However, the development of synthesis methods to fabricate uniform garnet-based micro and nanoparticles, that are needed for such applications, is not mature at all. This study reports the synthesis of highly uniform yttrium aluminum gallium garnet nanospheres. The method is based on homogeneous precipitation in a polyol medium followed by silica coating and calcination. The nanoparticles resulting after silica removal were also uniform and were easily functionalized with polyacrylic acid. The colloidal stability of the latter in physiological media and their biocompatibility were analyzed. The luminescence of the particles, doped with Ce3+, Cr3+, and Nd3+, was studied by recording emission and excitation spectra and persistent luminescence decay curves. Due to their uniform morphology, high colloidal stability, absence of toxicity, and persistent emission in the visible and near-infrared regions, the reported nanospheres show great potential as persistent luminescent bioimaging probes. In addition, the synthesis method paves the way for future use of this persistent material in other applications that require the phosphor to be in the form of highly uniform nanoparticles.
This publication is part of the I +D+I Grants RTI2018-094426-B-I00 and PID2020-118485RB-I00 funded by MCIN/AEI/10.13039/501100011033, by “ERDF A way of making Europe”, and the Fondo Social de la DGA (grupos DGA). Financial support was also provided by Junta de Andalucía (P20_00182). Grants FPU19/00527 and FPU19/01311 were funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”. This research work was performed in the framework of the Nanomedicine CSIC HUB (Ref. 202180E048).