Gold nanobipyramid-loaded black phosphorus nanosheets for plasmon-enhanced photodynamic and photothermal therapy of deep-seated orthotopic lung tumors

Abstract

Various types of photodynamic agents have been explored for photodynamic therapy (PDT) to destroy cancers located in deep tissues. However, these agents are generally limited by low singlet oxygen (¹O₂) yields owing to weak absorption in the optical transparent window of biological tissues. Accordingly, in this work, we developed a nanocomposite through the assembly of gold nanobipyramids (GNBPs) on black phosphorus nanosheets (BPNSs). This nanocomposite could simultaneously enhance ¹O₂ generation and hyperthermia by localized surface plasmon resonance in cancer therapy. As two-dimensional inorganic photosensitizers, BPNSs were hybridized with GNBPs to form BPNS-GNBP hybrid nanosheets. The hybridization markedly increased ¹O₂ production by the BPNSs through plasmon-enhanced light absorption. The nanocomposite exhibited a higher photothermal conversion efficiency than the BPNSs alone. In vitro and in vivo assays indicated that the BPNS-GNBP hybrid nanocomposite exhibited good tumor inhibition efficacy owing to simultaneous dual-modality phototherapy. In vivo, the nanocomposite suppressed deep-seated tumor growth with minimal adverse effects in mice bearing orthotopic A549 human lung tumors. Taken together, these results demonstrated that our BPNS-GNBP nanocomposite could function as a promising dual-modality phototherapeutic agent for enhanced cancer therapy in future cancer treatments. STATEMENT OF SIGNIFICANCE: In this study, we established a new nanocomposite by assembly of gold nanobipyramids (GNBPs) on black phosphorus nanosheets (BPNSs). Characterization of this nanocomposite showed that BPNS-GNBP enhanced ¹O₂ generation and hyperthermia. BPNS-GNBP exhibited good tumor inhibition efficacy in vivo and in vitro owing to simultaneous dual-modal phototherapy functions. Moreover, BPNS-GNBP suppressed deep-seated tumor growth in vivo and did not show adverse effects in mice bearing orthotopic A549 human lung tumors. Overall, these results showed that BPNS-GNBP may be used as a promising dual-modal phototherapeutic agent for enhanced cancer therapy in future clinical applications.

Keywords: Black phosphorus nanosheets; Gold nanobipyramids; Lung cancer; Photodynamic therapy; Photothermal therapy.