Progress in the Development of Metal-Organic Frameworks (MOFs) for Medical Imaging of Tumors: Prospects and Challenges.

Metal-organic frameworks (MOFs) are an emerging class of porous nanomaterials for tumor imaging owing to their tunable porosity, exceptionally high surface area, confinement effect, and high density of active sites, which collectively enable superior loading efficiency, signal amplification, and multifunctionality compared with conventional nanoplatforms. This review is a general overview of the advances that have been conducted in the development of imaging agents based on MOFs, with the perspective of their use in different imaging modalities such as magnetic resonance imaging (MRI), positron emission tomography (PET), fluorescence imaging, and computed tomography (CT). All the peculiarities of MOFs, including the possibility to introduce a metal, adjust the surface, and combine different imaging methods into one are described in detail. We also discuss the application of MOFs to tumor targeting and drug delivery and how this system can be functionalized to allow targeting of tumors and the possibility of personalized therapy. Despite these advantages, major barriers including complex synthesis, limited physiological stability, potential toxicity, scalability issues, and regulatory constraints continue to widen the bench-to-bedside gap and hinder the clinical translation of MOF-based imaging systems. New technologies in the design of MOFs, including hybrid and multifunctional MOFs, present new possibilities to improve imaging sensitivity, resolution, and therapeutic success. Future perspectives including theranostic integration and potential clinical applications of MOF-based imaging platforms are also discussed. Finally, despite the presence of multiple challenges, MOFs can be used to revolutionize the field of tumor imaging and enhance the process of cancer diagnosis and treatment with more sensitive, targeted, and personalized strategies.