Metal Organic Frameworks as Drug Targeting Delivery Vehicles in the Treatment of Cancer

Abstract

: In recent years, metal organic frameworks (MOFs) have been widely developed as vehicles for the effective delivery of drugs to tumor tissues. Due to the high loading capacity and excellent biocompatibility of MOFs, they provide an unprecedented opportunity for the treatment of cancer. However, drugs which are commonly used to treat cancer often cause side effects in normal tissue accumulation. Therefore, the strategy of drug targeting delivery based on MOFs has excellent research significance. Here, we introduce several intelligent targeted drug delivery systems based on MOFs and their characteristics as drug-loading systems, and the challenges of MOFs are discussed. This article covers the following types of MOFs: Isoreticular Metal Organic Frameworks (IRMOFs), Materials of Institute Lavoisier (MILs), Zeolitic Imidazolate Frameworks (ZIFs), University of Oslo (UiOs), and MOFs-based core-shell structures. Generally, MOFs can be reasonably controlled at the nanometer size to effectively achieve passive targeting. In addition, different ligands can be modified on MOFs for active or physicochemical targeting. On the one hand, the targeting strategy can improve the concentration of the drugs at the tumor site to improve the efficacy, on the other hand, it can avoid the release of the drugs in normal tissues to improve safety. Despite the challenges of clinical application of MOFs, MOFs have a number of advantages as a kind of smart delivery vehicle, which offer possibilities for clinical applications.

Keywords: metal organic framework; nanoparticle; targeting drug delivery system.

Figure 1

ZIF-90 nanoparticles (NPs) synthesized in trioctylamine at (A) 0 °C, (C) 100 °C, and (E) 150 °C and particles synthesized at room temperature using (B) trioctylamine, (D) tributylamine, (F) trimethylamine [12]. Reprinted (adapted) with permission from (Versatile Synthesis and Fluorescent Labeling of ZIF-90 Nanoparticles for Biomedical Applications). Copyright (2016) American Chemical Society.

Figure 2

Schematic diagram of the types of tumor-targeted treatment strategies based on MOFs.

Figure 3

Schematic diagram of targeting of Eu(III) -based nanoscale metal organic framework to the tumor site and realized photodynamic therapy under the excitation of 808 nm near infrared light [20]. Reprinted (adapted) with permission from (Functionalized Eu(III)-Based Nanoscale Metal–Organic Framework To Achieve Near-IR-Triggered and -Targeted Two-Photon Absorption Photodynamic Therapy). Copyright (2018) American Chemical Society.

Figure 4

Schematic illustration of the combinational therapy platform based on folic acid (FA)−bovine serum albumin (BSA)-modified ZIF-8 (FA−BSA/CuS@ZIF-8-QT) [90]. Reprinted (adapted) with permission from (CuS@MOF-Based Well-Designed Quercetin Delivery System for Chemo–Photothermal Therapy). Copyright (2018) American Chemical Society.