Preparation of Nanoparticle Probes for Multimodal Bio-imaging

Abstract

The nanoparticles of solid solutions between Y₃Al₅O₁₂ （YAG） and Gd₃Al₅O₁₂ （GAG） are synthesized from yttrium acetate tetrahydrate, gadolinium acetate tetrahydrate and aluminum isopropoxide at different Y/Gd atomic ratios in 1,4-butanediol by autoclave treatment at 300℃ for 2 h, i.e., by the glycothermal reaction. On the other hand, Yb³⁺ doped Y₃Al₅O₁₂ （YAG:Yb³⁺） nanoparticles are prepared from yttrium acetate tetrahydrate, ytterbium acetate tetrahydrate and aluminum isopropoxide in 1,4-butanediol by autoclave treatment at 300℃ for 2 h. Moreover, Gd-YAG and Gd-YAG:Yb³⁺ nanoparticles are prepared from the mixture of gadolinium acetate tetrahydrate and either YAG or YAG:Yb³⁺ colloidal solution by the same autoclave treatment as YAG:Yb³⁺. Properties of structure, near infrared photoluminescence and magnetic resonance contrast enhancement are characterized for as-prepared nanoparticles. The solid solutions between YAG and GAG work as T₂ contrast agent for magnetic resonance imaging, while Gd-YAG works as T₁ and T₂ contrast agents. Gd-YAG:Yb³⁺ nanoparticles work as T₁ and T₂ contrast agents like Gd-YAG nanoparticles, and show near infrared emission at 1030 nm due to the f-f transition of Yb³⁺ under the 940 nm excitation using near infrared laser diode.