Single injection and multiple treatments: An injectable nanozyme hydrogel as AIEgen reservoir and release controller for efficient tumor therapy

Direct intratumoral injection of aggregation-induced emission luminogen (AIEgen) enable direct photodynamic therapy (PDT) of tumors, but these injections may cause localized pain and a range of postoperative complications during frequent injections. In the present study, we developed a novel injectable nanozyme hydrogel that functions as AIEgens reservoir and release controller (ARC) and thereby facilitates more efficient tumor therapy. The ARC system was developed by simultaneously encapsulating Prussian blue (PB) nanoparticles and an AIEgen (CQu) in agarose hydrogels. PB converts near-infrared laser into heat, resulting in agarose degradation and consequent CQu release. Then PB nanozyme can drive the decomposition of endogenous hydrogen peroxide, then yielding oxygen (O-2) generation. Following subsequent low-power white light exposure, AIEgens can generate high levels of reactive oxygen species (ROS) with sufficient O-2, thereby inducing tumor cell cytotoxicity. As hydrogels can persist within tumors for a minimum of 48 h, they can facilitate multiple rounds of treatment following a single injection. The present study is the first attempt to utilize hydrogel for AIEgens delivery, and the ARC system developed herein offers a novel means of supporting the clinical development of AIEgens treatment strategies for cancer patients. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The ARC system developed in this study converts near-infrared laser into heat, releases AIEgens, drives the decomposition of endogenous hydrogen peroxide, generates sufficient oxygen for high levels of reactive oxygen species to induce tumor cell cytotoxicity, and the hydrogel can persist for at least 48 hours, supporting multiple rounds of treatment.