Ultrathin Black Phosphorus Nanosheets for Efficient Singlet Oxygen Generation

TLDR

Singlet oxygen is a powerful oxidant studied across disciplines, yet conventional photosensitizers suffer from low quantum yields, limited absorption, poor biocompatibility, and lack of degradability. The study aims to develop ultrathin black phosphorus nanosheets as efficient, biocompatible photosensitizers for singlet‑oxygen generation and photodynamic cancer therapy. Exfoliated black phosphorus nanosheets exhibit a high singlet‑oxygen quantum yield (~0.91), effective in vitro and in vivo photodynamic cancer therapy, and photodegrade into biocompatible phosphorus oxides.

Abstract

Benefiting from its strong oxidizing properties, the singlet oxygen has garnered serious attentions in physical, chemical, as well as biological studies. However, the photosensitizers for the generation of singlet oxygen bear in low quantum yields, lack of long wavelength absorption band, poor biocompatibility, undegradable in living tissues, and so on. Here we first demonstrate the exfoliated black phosphorus nanosheets to be effective photosensitizers for the generation of singlet oxygen with a high quantum yield of about 0.91, rendering their attractive applications in catalysis and photodynamic therapy. Through in vitro and in vivo studies, the water dispersible black phosphorus nanosheets show notable cancer therapy ability. In addition, the photodegradable character of black phosphorus from element to biocompatible phosphorus oxides further highlights its therapeutic potential against cancer. This study will not only expand the breadth of study in black phosphorus but also offer an efficient catalyst and photodynamic therapy agent.