Black Phosphorus in Biological Applications: Evolutionary Journey from Monoelemental Materials to Composite Materials

ConspectusUnderstanding the evolutionary journey of monoelemental black phosphorus (BP) to BP-based composites plays a crucial role in expanding and advancing the development of BP in biological applications. Because of its exceptional unique structure and superior biological properties, BP has been extensively developed into various nanomaterials for different biological applications. However, the performance of BP alone cannot completely meet some specific requirements, and one possible route to harnessing its unique properties for different biological applications is to incorporate BP with a specific material to obtain an on-demand composite material. The manufacturing of such high-performance composites requires not only a full understanding of the structure and features of BP so that it could be perfectly incorporated with other materials or homogeneously distributed into various matrixes but also a clear biological effect of BP in different biological applications. Therefore, we summarize our recent work on BP-based high-performance composites for different biological applications, aiming to uncover (i) the evolutionary journey of BP from monoelemental materials to composite materials in biological applications and (ii) the interaction between BP and biological systems.Since the emergence of BP, BP-based materials have shown a prominent potential for technological applications as well as plenty of unexplored fundamental science. In particular, with the unlimited potential of BP in biological fields, it is desirable to take advantage of the useful performance of BP in composites through the combination of various functional materials for broadening its bioapplications. However, how to design and synthesize a BP-based composite with some specific performance remains a huge challenge due to the lack of an in-depth understanding of the interaction among BP, functional adjuvants, and physiological systems. BP-based nanosheets can selectively kill tumor cells via a reactive oxygen species (ROS)-mediated mechanism that indicates the biological effects of BP in physiological systems. Understanding the nanobio interaction of monoelemental BP materials can better make clear its fate in physiological systems, thereby contributing to the introduction of different functional adjuvants to decorate BP to obtain high-performance BP-based composite for different bioapplications. In addition, the functionalization or decoration of BP to form an additive-supported BP-based composite will further augment the performance of BP-based nanomaterials and broaden their bioapplication range. Owing to its high specific surface area and strong metal ion binding ability, BP nanosheets can serve as an ideal matrix to incorporate with small molecular drugs, metal ions, or metal nanostructures to obtain a multifunctional BP-based composite with enhanced properties for effective cancer therapy and photo/biocatalytic CO2 reduction. The combination of BP and the biomimetic matrix can also augment the performance of BP-based composites; therefore, fibrin gel with strong tissue healing could serve as an artificial skin to endow BP-based fibrin gel with excellent antibacterial ability, analgesia, and wound healing for diabetic ulcer therapy. Finally, we also outlook the future development and challenges as well as the clinical application prospect of an additive-supported BP-based composite.