Carbon-based dot-capped gold nanoparticles hybridized with manganese dioxide for enhanced photodynamic cancer therapy

Abstract

Carbon-based dot-capped gold nanoparticles (AuNPs/CDs) were synthesized and found to exhibit high singlet oxygen (¹O₂) generation capability owing to the synergistic effect of the strong localized surface plasmon resonance (LSPR) absorption of AuNPs and high ¹O₂ yield of CDs. The obtained AuNPs/CDs were further hybridized with folic acid (FA)-modified and CD-capped manganese dioxide nanosheets (FA/MnO₂/CDs). The hybridization-induced aggregation produced a new and strong LSPR absorption peak of AuNPs at around 680 nm. Furthermore, MnO₂ nanosheets in the obtained FA/MnO₂/CDs-AuNPs/CDs nanohybrids could react with intracellular H₂O₂ to release O₂, which could relieve the tumor hypoxia microenvironment. The ¹O₂ quantum yield of the nanohybrids under 660 nm laser irradiation was about 1.05% in the absence of H₂O₂ and increased to 2.60% in the presence of 1 × 10⁻⁵ mol L⁻¹ H₂O₂. In vitro cell viability studies demonstrate that >95% of HeLa cells were killed by treatment with FA/MnO₂/CDs-AuNPs/CDs under irradiation (660 nm, 2.5 W cm⁻²) for 20 min. The as-developed nanohybrids are thus proved to be promising photosensitizers for photodynamic therapy applications.