Surface modification of black phosphorus-based nanomaterials in biomedical applications: Strategies and recent advances

Black phosphorus-based nanomaterials (BPNMs), an emerging member of two-dimensional (2D) nanomaterials, possess excellent physicochemical properties and hold great potential for application in advanced nanomedicines. However, the bare BPNMs easily decrease their biomedical activities due to their degradability and in vivo interactions with biological macromolecules such as plasma proteins, largely restricting their biomedical application. A variety of surface modifications, via chemical, physical or biological approaches, have been developed for BPNMs to avoid these limitations and achieve stable, long-lasting and safe therapeutic effects, thus enlighten the development of the multifunctional BPNMs for more practical application in the field of biomedicine. The present review summarizes the recent advances in the surface modification of BPNMs and the resultant expansion of their biomedical applications. Focus is put on the strategy and method of modification while the effects incurred on the behavior and potential toxicity of BPNMs are also included. The future and challenge of the surface modification of the therapeutic BPNMs are finally discussed.