Localized Surface Plasmon Resonance Enhanced Singlet Oxygen Generation and Light Absorption Based on Black Phosphorus@AuNPs Nanosheet for Tumor Photodynamic/Thermal Therapy

Although photodynamic therapy is an efficient therapeutic strategy for cancer treatment, it always suffers from the low singlet oxygen (O-1(2)) yields owing to the weak absorption in optical transparent window of biological tissues. Herein, the black phosphorus (BP) nanosheet is integrated with gold nanoparticles (AuNPs) to simultaneously enhance the singlet oxygen generation and hyperthermia by localized surface plasmon resonance (LSPR) in cancer therapy. In the design, BP nanosheet employed as two-dimension (2D) inorganic photosensitizer is hybridized with AuNPs through polyetherimide (PEI) as bridge to form BP-PEI/AuNPs hybrid nanosheet. Such hybridation not only significantly increases the O-1(2) production of BP nanosheet through maximizing the local field enhancement of AuNPs, but also significantly enhances the light absorption of BP nanosheet to promote photothermal effect by LSPR. Accordingly, about 3.9-fold enhancement of O-1(2) production and 1.7-fold increasement of photothermal conversion efficiency are achieved compared with BP-PEI alone upon single 670 nm laser irradiation. As a proof-of-concept model, BP-PEI/AuNPs hybrid nanosheet with simultaneous dual-modal phototherapy functions result in effective suppression of tumor growth with minimized side effects both in vitro and in vivo, indicating the great potential of the BP-PEI/AuNPs hybrid nanosheet as an effective strategy to enhance the cancer therapy efficiency.