MRI‐Active Metal‐Organic Frameworks: Concepts for the Translation from Lab to Clinic

Abstract

Metal‐organic frameworks (MOFs) are an emerging class of synthetic materials obtained by combining organic and inorganic chemistry. MOFs show peculiar properties such as well‐defined crystalline structures, systematic structural variation, high porosity and the possibility to chemically functionalize the pores. These properties are especially promising for designing MOF nanoparticles (NPs) with special functions. The desired functions can be introduced and modified with a chemical approach, by the choice of the inorganic and organic building blocks. All these features and the highest surface area of any porous material make MOF NPs ideal for the use as nanocarrier in biomedicine. So far, a wide variety of biomedical applications of MOF NPs have been already envisioned being supported by promising first in vitro and in vivo results. The ongoing development of MOF NPs is at the edge of basic science to biomedical applications. A major focus of biomedical research is already in cancer therapy using MOF NPs as theranostic nanocarrier. In this article, NP designs and MRI‐labelling concepts are pointed out and discussed in the perspective of facilitating their translation to clinical use. Clinical application is envisioned with a major focus on theranostic MOF NPs and MRI as the most promising imaging method.

Reticular Nanoscience: Bottom-Up Assembly Nanotechnology

“…This leads to extremely high drug (probe) loading capacities and lowers structural and design complexity by eliminating the need for external carriers, which could ultimately facilitate the clinical translation and manufacturing of nanopharmaceuticals. First examples of this strategy are the use of MOF nanoparticles (i) as contrast agents for magnetic resonance imaging (MRI), computed tomography (CT), and/ or positron emission tomography (PET) by building them with MRI-, CT-or PET-active metal ions or linker molecules; 107 (ii) in photodynamic therapy (PDT), 108,109 built from photosensitizing (metallo)linker molecules or in photothermal therapy (PTT) from photoconverting linkers; 110 and (iii) constituted by pro-drug building units, linkers, and metal ions. 111 Notably, the assembly of different, biocompatible building units into MOF nanoparticles has already been shown to trigger biological effects in cells, such as pyroptosis, 112 ferroptosis, 113 and immune-related responses, 114 that would not be mediated by the individual building units alone.…”

Progressive Trends on the Biomedical Applications of Metal Organic Frameworks

“…MRI is superior to any optical imaging technique in terms of penetration depth confront [ 89 ]. The magnetic relaxivity enhances the MRI image contrast.…”

Recent Advances in Metal–Organic Frameworks for Applications in Magnetic Resonance Imaging

“…MOFs are porous crystalline coordination polymers. − They consist of metal ions (or clusters) and bridging ligands. Due to their design variety, tunable properties, and extremely high surface area, they have been investigated in many different applications including gas storage and separation, − catalysis, , sensing, , and also medical areas. − In medicine, due their porosity (and thus a high loading capacity), they have been suggested as highly promising materials for drug delivery applications. − Recently, also their applications in diagnostics have been examined for various imaging modalities, including fluorescence and photoacoustic imaging, , but mainly MRI. , The early stages of MOFs for applications in MRI were reviewed in the beginning of 2018 by Wuttke et al, who reviewed about 25 publications . Since then, the field has expanded rapidly resulting in about 161 publications (August 2022, Figure ).…”