Core-shell metal-organic frameworks with fluorescence switch to trigger an enhanced photodynamic therapy

Abstract

The design of hybrid metal-organic framework (MOF) nanomaterials by integrating inorganic nanoparticle into MOF (NP@MOF) has demonstrated outstanding potential for obtaining enhanced, collective, and extended novel physiochemical properties. However, the reverse structure of MOF-integrated inorganic nanoparticle (MOF@NP) with multifunction has rarely been reported. <b>Methods</b>: We developed a facile in-situ growth method to integrate MOF nanoparticle into inorganic nanomaterial and designed a fluorescence switch to trigger enhanced photodynamic therapy. The influence of "switch" on the photodynamic activity was studied <i>in vitro</i>. The <i>in vivo</i> mice with tumor model was applied to evaluate the "switch"-triggered enhanced photodynamic therapy efficacy. <b>Results</b>: A core-satellites structure with fluorescence off and on function was obtained when growing MnO₂ on the surface of fluorescent zeolitic imidazolate framework (ZIF-8) nanoparticles. Furthermore, A core-shell structure with photodynamic activity off and on function was achieved by growing MnO₂ on the surface of porphyrinic ZrMOF nanoparticles (ZrMOF@MnO₂). Both the fluorescence and photodynamic activities can be turned off by MnO₂ and turned on by GSH. The GSH-responsive activation of photodynamic activity of ZrMOF@MnO₂ significantly depleted the intracellular GSH via a MnO₂ reduction reaction, thus triggering an enhanced photodynamic therapy efficacy. Finally, the GSH-reduced Mn²⁺ provided a platform for magnetic resonance imaging-guided tumor therapy. <b>Conclusion</b>: This work highlights the impact of inorganic nanomaterial on the MOF properties and provides insight to the rational design of multifunctional MOF-inorganic nanomaterial complexes.