As a new type of 2D material, BP nanosheets (BPNSs) have attracted much attention owing to their unique 2D layered structure and layer-dependent bandgap of 0.3-2.0 eV. BPNSs have recently been adopted for photodynamic therapy, photothermal therapy, and drug delivery in theranostic nanomedicine. However, the weak light absorption of BPNSs in the optically transparent window of biological tissues limits ¹O₂ generation and PTT（photothermal therapy）efficiency in treating deep tumors. While combining with other nanomaterials, both PDT（photodynamic therapy）and PTT can theoretically achieve higher efficiency, this possibility has not yet been sufficiently explored.

Recently, a research group led by professor LIU Jun from Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences had made achievements on BPNSs combination with GNBPs (gold nanobipyramids) through plasmon excitation of improved ¹O₂ generation for PDT and localized hyperthermia for PTT. Their result was published in Acta Biomaterialia.

In the study, they 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 showed 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 demonstrate that BPNS-GNBP nanocomposite can function as a promising dual-modality phototherapeutic agent for enhanced cancer therapy in future cancer treatments.

This work was supported by the National Natural Science Foundation of China and the Shanghai Sailing Program.

Schematic illustration of the preparation of the BPNS-GNBP nanocomposite and LSPR-enhanced PDT-PTT. (Image by SIOM)

Article website:
https://doi.org/10.1016/j.actbio.2020.03.001

Contact:
Mr. CAO Yong
General Administrative Office
Shanghai Institute of Optics and Fine Mechanics, CAS
Email: caoyong@siom.ac.cn