The synergistically improved afterglow and magnetic resonance imaging induced by Gd3+ doping in ZGGO:Cr3+ nanoparticles

Gd 3+ and Cr 3+ codoped zinc gallogermanate (ZGGO:Cr 3+ , Gd 3+ ) nanoparticles were prepared by a hydrothermal method in combination with a subsequent vacuum annealing. It is found that Gd 3+ doping not only endows ZGGO:Cr 3+ nanoparticles with magnetic property, but also results in the decreased nanoparticle size and the enhanced near infrared (NIR) afterglow intensity. Strikingly, amino group functionalized SiO 2 layer coating enabling Gd 3+ doped ZGGO:Cr 3+ nanoparticles well dispersed in water enhances persistent luminescence which is because of the weakened quenching effect of OH − groups in water. Validation of high-quality bioimaging was demonstrated using the surface functionalized Gd 3+ doped ZGGO:Cr 3+ nanoparticles dispersed in human serum albumin (HSA). In particular, it is found that the longitudinal relaxivity (7.33 s −1 (mM) −1 ) of Gd 3+ doped ZGGO:Cr 3+ nanoparticles is higher than that of commercial magnetic resonance imaging (MRI) contrast agent (Gd-DTPA) and it leads to the high-quality in vitro T 1 -weigthed images.