Multifunctional near infrared-emitting long-persistence luminescent nanoprobes for drug delivery and targeted tumor imaging

In this paper, near infrared-emitting long-persistence luminescent porous Zn1.1Ga1.8Ge0.1O4:Cr3+, Eu3+ @SiO2 nanoprobes have been prepared using mesoporous silica nanospheres both as morphology-controlling templates and as vessels. These nanoprobes possessed an excellent capacity for drug delivery and allowed for real-time monitoring of the delivery routes of the drug carriers in vivo. The nanoprobes demonstrated a typical mesoporous structure, a brighter NIR emission (696 nm) and a long afterglow luminescence that persisted for 15 d. Furthermore, after surface modification with folic acid (FA), a tumor-targeting group, these nanoprobes exhibited an excellent ability to target tumors with high sensitivity in vitro and in vivo. Importantly, these modified nanoprobes could accurately diagnose tumors and allow for long-term tumor monitoring via in situ and in vivo re-excitation by a red LED lamp. Furthermore, the drug release data demonstrated that the modified nanoprobes could be loaded with a large amount of doxorubicin hydrochloride (DOX) and showed sustained release behavior. Together, the results of this study indicate that these nanoprobes can accurately diagnose tumors, allow for long-term in vivo and in situ monitoring and release DOX in situ to cure tumors.