A facile synthesis of strong near infrared fluorescent layered double hydroxide nanovehicles with an anticancer drug for tumor optical imaging and therapy

In this work, a new multifunctional nanovehicle for tumor optical imaging and therapy was developed using Y₂O₃:Er ³⁺,Yb³⁺ nanoparticles as near infrared fluorescent nanophosphors, and MgAl-layered double hydroxide (LDH) nanosheets as anticancer drug nanovehicles. Monodispersed Y₂O₃:Er ³⁺,Yb³⁺ nanophosphors were readily synthesized by the urea assisted homogenous precipitation method. Hierarchically structured LDH nanosheets intercalated with an anticancer drug, fluorouracil (5FU), were deposited on the surface of Y₂O₃:Er³⁺,Yb ³⁺@SiO₂ by a simple precipitation method followed by hydrothermal treatment. The resultant Y₂O₃:Er ³⁺,Yb³⁺@SiO₂@LDH-5FU nanovehicles exhibit strong red upconversion fluorescence under the excitation of a 980 nm laser, which allows tracking of the nanovehicles after localization in cancer cells. A better anticancer efficiency was obtained over the nanovehicles than the free drug which can be attributed to their positively charged surfaces for favorable interaction with the negatively charged cell membranes. The multifunctional nanovehicles designed in this work are expected to be promising material candidates for simultaneous tumor optical imaging and therapy. © 2013 The Royal Society of Chemistry.