Synthesis, luminescence, and anti-tumor properties of MgSiO3:Eu-DOX-DPP-RGD hollow microspheres

Abstract

In this report, MgSiO₃:Eu-DOX-DPP-RGD hollow microspheres employed for simultaneous imaging and anti-cancer therapy have been designed by sequentially loading the anti-tumor drugs doxorubicin (DOX), light-activated platinum(IV) pro-drug PPD, and a targeted peptide of NH₂-Gly-Arg-Gly-Asp-Ser (RGD) onto MgSiO₃:Eu mesoporous hollow spheres, which were synthesized using solid SiO₂ spheres as sacrificed template by a facile hydrothermal process based on the Kirkendall effect. The photoluminescence intensity of MgSiO₃:Eu has been optimized, which can emit a recognized red signal in vitro and in vivo under modest ultraviolet (UV) irradiation. It was found that the platform has high biocompatibility and could become intracellular through fast and effective endocytosis with the aid of the targeted peptide RGD, and chemotherapeutic drugs DOX and light-activated platinum(IV) pro-drug DPP that can be released from the carrier to induce an obvious inhabitation effect to HeLa cancer cells (survival rate of only 17.4%), which has been verified by in vitro and in vivo results. Moreover, the in vitro result using a photosensitizer ZnPc loaded carrier shows that the system is not suitable for ZnPc induced photodynamic therapy. The apparent imaging effect and high anti-tumor efficacy of this functional system give it great potential in actual clinical applications.