Polypyrrole@MnO2 fluorescence nanocomposites as a multifunctional architecture for glutathione sensing and synergistic therapy of cancer

A tumor microenvironment responsive nanoarchitecture was designed for glutathione (GSH) sensing and synergistic photothermal/photodynamic therapy. Using polymer dots as both templates and reductants, MnO 2 was coated on their surface via in-situ reaction to harvest fluorescence PDs@MnO 2 nanoprobes. The photosensitizer methylene blue doped polypyrrole nanocomposites were synthesized by one-pot method, and further modified with silica to prepare PPy@MB-SiO 2 nanocomposites, PPy@MB-SiO 2 /PDs@MnO 2 nanoarchitecture was finally constructed based on electrostatic interaction. MnO 2 was responsible for the fluorescence quenching of PDs through fluorescence resonance energy transfer, while GSH induced the degradation of MnO 2 to promote fluorescence recovery. A fluorescence sensing GSH method was thus established, the fluorescence intensity of this nanoarchitecture exhibited a linearity in GSH concentrations range from 1 to 250 μmol·L −1 with a detection limit of 0.16 μmol·L −1 (3σ). MnO 2 also ensured the amelioration of tumor hypoxia, hence more 1 O 2 was generated to improve photodynamic therapy effect. Polypyrrole was in charge of photothermal performance that bestowed this nanoarchitecture with 31.45 % of photothermal conversion efficiency. Particularly, this platform was able to distinguish cancer cells and normal cells. The overexpression of GSH in HeLa cells stimulated fluorescence recovery, while only weak fluorescence was observed in Raw cells, this platform thus realized the fluorescence imaging recognition of cancer cells. The combined therapy effect was further harvested under 808 and 635 nm laser irradiation. The integration of fluorescence imaging, photothermal and photodynamic therapy in one platform that satisfied the need of cancer diagnosis and treatment. This strategy had reference significance for the assembly of multi-responsive therapy architectures.