Recent Progress of Metal-Organic Framework-Based Photodynamic Therapy for Cancer Treatment

Abstract

Photodynamic therapy (PDT), combining photosensitizers (PSs) and excitation light at a specific wavelength to produce toxic reactive oxygen species, has been a novel and promising approach to cancer treatment with non-invasiveness, spatial specificity, and minimal systemic toxicity, compared with conventional cancer treatment. Recently, numerous basic research and clinical research have demonstrated the potential of PDT in the treatment of a variety of malignant tumors, such as esophageal cancer, bladder cancer, and so on. Metal-organic framework (MOF) has been developed as a new type of nanomaterial with the advantages of high porosity, large specific surface area, adjustable pore size, and easy functionalization, which could serve as carriers to load PSs or increase the accumulation of PSs in target cells during PDT. Moreover, active MOFs have the potential to construct multifunctional systems, which are conducive to refining the tumor microenvironment (TME) and implementing combination therapy to improve PDT efficacy. Hence, a comprehensive and in-depth depiction of the whole scene of the recent development of MOFs-based PDT in cancer treatment is desirable. This review summarized the recent research strategies of MOFs-based PDT in antitumor therapy from the perspective of MOFs functions, including active MOFs, inactive MOFs, and their further combination therapies in clinical antitumor treatment. In addition, the bottlenecks and obstacles in the application of MOFs in PDT are also described.

Nanoscale metallic‐organic frameworks as an advanced tool for medical applications: Challenges and recent progress

“…Conventional PSs are chlorophylls, porphyrins, or organic dyes. [89] A novel approach is to use nanocarriers for selective delivery of PSs to cancerous tissues through the EPR phenomenon. Another strategy is the active targeted delivery via binding ligands to receptors that are overexpressed in tumors.…”

“…[90] Although several nanocarriers have been proposed for the effective and safe distribution of PSs to cancerous cells, most of them have disadvantages such as low drug loading, poor biocompatibility, low stability, and no repeatability. Among the proposed nanocarriers, MOFs seem to be the most suitable materials because they show enhanced stability, are able to reduce the toxicity of PSs, to effectively target then to cancer cells, to attain a delayed-release, [89] and to optimize the generation and transport of ROS to intracellular organelles. [91] The design of porphyrin-based MOFs by introducing porphyrin molecules into MOFs or using porphyrins as organic linkers to form MOFs can result in compounds with unique properties due to synergistic effects.…”

Research progress in inducing immunogenic cell death of tumor cells

“…They can induce ICD response in tumor cells, eliminate tumor cell drug resistance, and promote tumor cell death. Their safe and effective anticancer effects provide a reliable alternative for patients with tumors suffering from underlying diseases who cannot tolerate chemotherapy ( 215 ).…”

A State-of-the-Art of Metal-Organic Frameworks for Chromium Photoreduction vs. Photocatalytic Water Remediation

“…Electron paramagnetic resonance (EPR) spectroscopy performed in specific spin trap molecules has been applied to qualitatively detect the • OH, 1 O 2 , and O 2 •− radicals generated by MOF photocatalysts [ 178 ]. The quantification of the radical generation during illumination conditions has been mainly reported for MOFs applied for photodynamic therapies [ 179 , 180 ] but it is starting to be applied for MOFs that are used for environmental purposes. Quantification of ROS is performed by colorimetric and fluorescence probe methodologies, where the concentration of the ROS is linked to the absorbance/fluorescence gain or loss or specific probe molecules.…”