Manganese Amplifies Photoinduced ROS in Toluidine Blue Carbon Dots to Boost MRI Guided Chemo/Photodynamic Therapy

Abstract

The contrast agents and tumor treatments currently used in clinical practice are far from satisfactory, due to the specificity of the tumor microenvironment (TME). Identification of diagnostic and therapeutic reagents with strong contrast and therapeutic effect remains a great challenge. Herein, a novel carbon dot nanozyme (Mn‐CD) is synthesized for the first time using toluidine blue (TB) and manganese as raw materials. As expected, the enhanced magnetic resonance (MR) imaging capability of Mn‐CDs is realized in response to the TME (acidity and glutathione), and r1 and r2 relaxation rates are enhanced by 224% and 249%, respectively. In addition, the photostability of Mn‐CDs is also improved, and show an efficient singlet oxygen (1O2) yield of 1.68. Moreover, Mn‐CDs can also perform high‐efficiency peroxidase (POD)‐like activity and catalyze hydrogen peroxide to hydroxyl radicals, which is greatly improved under the light condition. The results both in vitro and in vivo demonstrate that the Mn‐CDs are able to achieve real‐time MR imaging of TME responsiveness through aggregation of the enhanced permeability and retention effect at tumor sites and facilitate light‐enhanced chemodynamic and photodynamic combination therapies. This work opens a new perspective in terms of the role of carbon nanomaterials in integrated diagnosis and treatment of diseases.

Spatiotemporally Controllable Bifunctional Micellar-Carbon Dot Supernanoparticles for Wounds Healing

“…Carbon dots (CDs), an up-and-coming carbon-based nanomaterial, have garnered significant interest in the field of photosensitizers for photodynamic therapy due to their small size, strong dispersion, high solubility, excellent biocompatibility, good photostability, and outstanding light-induced charge transfer rate. ,,− Moreover, the easily modifiable structural characteristics render carbon dots more straightforward, efficient, and cost-effective in realizing multifunctional synergistic effects. , Doping CDs with metal ions is a potent tactic for modulating their physicochemical properties. ,− Cerium (Ce) is the most prevalent rare earth metal in the Earth’s crust. , Nanomaterials containing cerium exhibit reversible conversion properties between Ce 3+ (reduced state) and Ce 4+ (oxidized state) in a biological environment . This redox cycling renders them an effective scavenger for free radicals, as they donate or accept electrons to neutralize unstable radicals, thereby exerting excellent and enduring antioxidant effects. − Meanwhile, as semiconductor photocatalysts, Ce-based nanomaterials exhibit strong absorption in the ultraviolet region. , When incorporated into carbon-based materials, Ce markedly enhances the suppression of electron–hole recombination and interaction with charge carriers, thereby significantly enhancing their ROS photocatalytic generation capability. ,− Ce-doped CDs are recognized as optimal nanomaterials with substantial application value for promoting wound healing.…”

Mg-ZIF nanozymes disrupt the level of ROS for osteosarcoma killing via POD activity

“…ZIF-derived nanoparticles have shown remarkable biocompatibility in prior studies ( Mi et al, 2021 ). Consequently, the development of ZIFs with POD-like enzymatic activity holds promise for catalyzing Fenton reactions ( Chu et al, 2023 ). Nanoparticles doped with magnesium (Mg) elements have been proven to possess catalytic activity for Fenton reactions; thus, doping ZIFs with Mg ions could potentially generate metal-organic frameworks with Fenton reaction catalysis capabilities.…”

Hybridized nanozymes for anti-osteosarcoma therapy via the Fenton reaction

“…Nanoparticles doped with manganese (Mn) have been shown to possess good POD-like activity. 17 Thus, if Mn ions can be doped into ZIFs, it may produce MOFs with POD-like activity. Furthermore, the excellent carrier functionality of ZIFs may facilitate future loading of other antitumor drugs or nanoparticles.…”