Preparation and drug-delivery properties of hollow YVO4:Ln3+and mesoporous YVO4:Ln3+@nSiO2@mSiO2(Ln = Eu, Yb, Er, and Ho)

In this paper, size-controlled morphologies of (Y, Gd)VO₄ and (Y, Gd)VO₄:Ln³⁺ (Ln = Eu, Yb, Er, and Ho) were obtained via a facile hydrothermal route, and their properties for drug delivery and photoluminescence were investigated. Monodisperse ellipsoid-like hollow (Y, Gd)VO₄ were designed by employing (Y, Gd)(OH)CO₃ colloidal spheres as a sacrificial template and NH₄VO₃ as a vanadium source, and the formation mechanism could be interpreted by the Kirkendall effect. The control of particle size for hollow (Y, Gd)VO₄ was realized, facilitating their practical application. Mesoporous core-shell structured (Y, Gd)VO₄:Ln³⁺@nSiO₂@mSiO₂ were designed to improve the properties for drug release. Typically, red emission of YVO₄:Eu³⁺ predominated under 465 nm excitation; the upconversion spectra of YVO₄:Yb³⁺, Er³⁺ and YVO₄:Yb³⁺, Ho³⁺ revealed green and red color upon 980 nm excitation, respectively. The biocompatibility and drug release evaluations indicate the potential biological applications of the samples.