Tumor-Activated and Metal–Organic Framework Assisted Self-Assembly of Organic Photosensitizers

Abstract

Tumor accumulation and intratumoral singlet oxygen (1O2) generation efficiency of photosensitizers (PSs) are two essential factors that determine their photodynamic therapy (PDT) efficacies. How to maximize the PS performance at the tumor site is of great research interest. Herein, we report a metal–organic framework (ZIF-8, ZIF = zeolitic imidazolate framework) assisted in vivo self-assembly nanoplatform, ZIF-8-PMMA-S-S-mPEG, as an effective tool for organic PS payloads to achieve efficient PDT. Using an organic PS with aggregation-induced emission as an example, under intratumoral bioreduction, PS-loaded ZIF-8-PMMA-S-S-mPEG (PS@ZIF-8-PMMA-S-S-mPEG) was self-assembled into large ordered hydrophobic clusters, which greatly enhance tumor retention and accumulation of the PS. Moreover, hydrophobic ZIF-8 assemblies greatly isolate the loaded PSs from water and improve O2 transport for the PSs to effectively produce 1O2 inside tumors under light irradiation. The organic PS is therefore endowed with optimal tumor accumulation and intratumoral 1O2 production, demonstrating the effectiveness of the developed self-assembly strategy in PDT application.

The fast-growing field of photo-driven theranostics based on aggregation-induced emission

“…As another kind of typical MOF, a zeolitic imidazolate framework (ZIF-8) was also applied to assist the self-assembly of AIE PSs and improve O 2 transportation, leading to the effective generation of ROS inside tumors for enhanced performance of PDT. 262 Besides TME-activated therapy for cancer, this strategy can also be appropriate for the fabrication of MOF-based nanotheranostics for precise antibacterial therapy and bacterial metabolic labeling, since bacterial infections have seriously threatened human health. Considering the urgent demand for noninvasive theranostic approaches toward bacteria, Kong et al reported MIL-100(Fe)-based nanocarriers for delivery of 3-azido-D-alanine (D-AzAla), which could selectively integrate into the walls of bacteria.…”

Temperature and pH Responsive Light‐Harvesting System Based on AIE‐Active Microgel for Cell Imaging

“…AIE materials provide another ideal choice for bioimaging. Some AIE nanomaterials including supramolecular assemblies, [ 25,26 ] metal–organic frameworks, [ 27 ] silica nanoparticles, [ 28 ] organic nanoparticles, [ 29,30 ] and nanocrystals, [ 31 ] have been developed for cell imaging. TPE based microgels may be another suitable candidates for celling imaging.…”

Doxorubicin-Loaded Metal-Organic Framework Nanoparticles as Acid-Activatable Hydroxyl Radical Nanogenerators for Enhanced Chemo/Chemodynamic Synergistic Therapy

“…Surprisingly, the strategies of delicately designed nanoparticles may help to solve these difficulties. A previous study shows that, due to their small size, nanoparticles self-aggregate in a tumor microenvironment with high levels of GSH, thus enhancing tumor retention and accumulation of the nanoparticles [34]. It has also widely been reported that the mechanism by which nanoparticles degrade within the tumor microenvironment accompanies the release of the loaded catalytic enzymes, such as poly(ethylene glycol)-modified glucose oxidase (GOx), to continuously generate •OH and enhance the killing effect of tumor cells [35,36].…”