Structural, microstructural and surface properties of colloidal Pt@TiO₂-rGO nanocomposite for biomedical applications.

This study reports a multifunctional Pt@TiO₂-rGO nanocomposite synthesized via a one-step solvothermal method and further PEGylated to enhance colloidal stability for biomedical applications. The nanocomposite integrates ultrasound-activated sonodynamic therapy (SDT), sono-thermal effects, radiotherapy dose enhancement, and enzyme-mimetic catalytic activity. Under ultrasound irradiation (1 MHz, 1 W·cm-2), the nanocomposite exhibits high sonocatalytic activity, achieving approximately 85% methylene blue degradation within 30 min, consistent with ROS-mediated activity under ultrasound and catalytic conditions. Sono-thermal studies (3 MHz, 2 W·cm-2) demonstrate a temperature increase up to 52.3 °C, highlighting its potential for localized thermal therapy. In radiotherapy experiments, Pt@TiO₂-rGO exhibited dose enhancement values reaching approximately 11.62% under 12 MeV electron irradiation, indicating its potential as a radiosensitizing platform for superficial treatment conditions. Additionally, the nanocomposite exhibits peroxidase-like activity through H₂O₂-mediated oxidation of OPD and catalase-like activity via H₂O₂ decomposition, supporting its role as a multifunctional nanozyme. These findings demonstrate that the Pt@TiO₂-rGO nanocomposite represents a versatile platform combining sonodynamic, thermal, catalytic, and radiotherapy-related functionalities. This integrated behavior highlights its potential for multimodal cancer therapy, although further biological and in vivo investigations are required to validate its clinical applicability.