Synthesis of iridium-based nanocomposite with catalase activity for cancer phototherapy.

The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted attention due to its enhanced tumor therapy effect. This study proposes a novel nanoenzyme-based theranostic nanoplatform, IrO2@MSN@PDA-BSA(Ce6), for the combined PTT and PDT of tumors. IrO2 was prepared by a simple hydrolysis method and coated with a thin layer of mesoporous silica (MSN) to facilitate the physical adsorption of Chlorin e6 (Ce6). The PDA coating and IrO2 NPs of the nanoplatform demonstrated an improved photothermal conversion efficiency of 29.8% under NIR irradiation. Further, the Ce6 loading imparts materials with the ability to produce reactive oxygen species (ROS) under 660 nm NIR laser irradiation. It was also proved that the IrO2 NPs could catalyze the hydrogen peroxide (H2O2) in the tumor microenvironment (TME) to generate endogenous oxygen (O2), thereby enhancing the efficiency of PDT. The in vitro and in vivo experiments indicated that the nanocomposite was highly biocompatible and could produce a satisfactory tumor therapeutic effect. Thus, the findings of the present study demonstrate the viability of using theranostic nanoenzymes for translational medicine.

Integration of Fe3O4 with Bi2S3 for Multi-Modality Tumor Theranostics.

The combination of reactive oxygen species (ROS)-induced chemodynamic therapy (CDT) and photothermal therapy (PTT) holds a promising application prospect for their superb anticancer efficiency. Herein, we created a novel Fe3O4@polydopamine (PDA)@bovine serum albumin (BSA)-Bi2S3 composite as a theranostic agent, by chemically linking the Fe3O4@PDA with BSA-Bi2S3 via the amidation between the carboxyl groups of BSA and the amino groups of PDA. In this formulation, the Fe3O4 NPs could not only work as a mimetic peroxidase to trigger Fenton reactions of the innate H2O2 in the tumor and generate highly cytotoxic hydroxyl radicals (•OH) to induce tumor apoptosis but also serve as the magnetic resonance imaging (MRI) contrast agent to afford the precise cancer diagnosis. Meanwhile, the PDA could prevent the oxidization of Fe3O4, thus supporting the long-term Fenton reactions and the tumor apoptosis in the tumor. The Bi2S3 component exhibits excellent photothermal transducing performance and computed tomography (CT) imaging capacity. In addition, the PDA and Bi2S3 endow the Fe3O4@PDA@BSA-Bi2S3 composite with an excellent photothermal transforming ability which could lead to tumor hyperthermia. All of these merits play the synergism with the tumor microenvironment and qualify the Fe3O4@PDA@BSA-Bi2S3 NPs for a competent agent in the MRI/CT-monitored enhanced PTT/CDT synergistic therapy. Findings in this research will evoke new interests in future cancer therapeutic strategies based on biocompatible nanomaterials.