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.

Preparation of Bi-based hydrogel for multi-modal tumor therapy.

Radiotherapy (RT) is becoming a pervasive therapeutic pattern in clinical cancer therapy. However, the hypoxic microenvironment of tumors has a strong resistance to radiotherapy and could lead to a potential recurrence and metastasis after the treatment. Therefore, the use of synergistic strategies for improving and supplementing the RT efficiency is important. Herein, a novel Bi2S3/alginate (ALG) hydrogel containing tirapazamine (TPZ) was designed for the effective suppression of tumor recurrence, by introducing Bi3+ into the ALG, Na2S and TPZ solution. In this formulation, Bi3+ was used to crosslink with the ALG to form the hydrogel and react with S2- to simultaneously form Bi2S3 nanoparticles in the hydrogel matrix. The resulting Bi2S3 nanoparticles not only exhibit the superb radiosensitization effect to boost the effective eradication of tumors during RT but also manifest an excellent photothermal transforming performance for tumor hyperthermia and computed tomography (CT) imaging capacity for tumor monitoring. Furthermore, the RT caused hypoxia could activate the reductive prodrug TPZ and enhance its therapeutic efficiency. The reported hydrogel system provides an efficient and safe therapeutic strategy for current local tumor therapy.