Defect-passivated metal halide perovskite quantum dots stabilized into biodegradable porous polydopamine nanoparticles for photothermal/chemodynamic/gas therapy of cancer

Herein, we reported a one-pot synthesis of CsPbBr₃ quantum dots (QDs) passivated with diammonium sulfide (NH₄)₂S additive using the probe-sonication technique. (NH₄)₂S-treated CsPbBr₃ (NS-CsPbBr₃) QDs exhibited superior optical properties compared to untreated QDs. The aqueous stability of NS-CsPbBr₃ QDs was improved by physical loading into porous manganese (Mn)-enriched polydopamine nanoparticles (mPDA NPs) via physical adsorption strategy, followed by functionalization with folic acid (FA), resulting in multifunctional nanospheres (denoted as NCPB@mPDA/FA NSs). The Mn²⁺ and S^2- ions in the NCPB@mPDA/FA NSs generated cytotoxic •OH radicals for chemodynamic treatment (CDT) and H₂S gas for gas therapy (GT) under acidic conditions, respectively. Furthermore, the intracellular antioxidant glutathione was significantly blocked using NCPB@mPDA/FA for enhanced CDT efficiency. Upon 808 nm laser irradiation, the green-emitting NCPB@mPDA/FA NSs demonstrated not only outstanding photothermal therapy (Ƞ=41.5%) due to considerable absorption in the near-infrared range but also stimulated the release of Mn²⁺ and S^2- ions for photothermal-triggered CDT and GT of cancer. The cancer cells effectively internalized NCPB@mPDA/FA through CD44 folate receptors, leading to a bright cellular image. Additionally, when combined with laser and H₂O₂, NCPB@mPDA/FA exhibited significant effectiveness against HeLa and 4T1 cells. Upon intravenous administration, NCPB@mPDA/FA exhibited notable tumor accumulation, resulting in enhanced tumor suppression in vivo, attributed to the improved hyperthermia-induced CDT and GT. The in vivo tumor inhibition potential of perovskite QD-based materials was demonstrated for the first time, indicating their therapeutic capabilities.