Emerging Violet Phosphorus Nanomaterial for Biomedical Applications

Violet phosphorus (VP) is a phosphorus allotrope first discovered by Hittorf in 1865, which has aroused more attention in the biomedical field in recent years attributed to its gradually discovered unique properties. VP can be further categorized into bulk VP, VP nanosheets (VPNs), and VP quantum dots (VPQDs), and chemical vapor transport (CVT), liquid-phase/mechanical/laser exfoliation, and solvothermal synthesis are the common preparation approaches of bulk VP, VPNs, and VPQDs, respectively. Compared with another phosphorus allotrope (black phosphorus, BP) that is once highly regarded in biomedical applications, VP nanomaterial (namely VPNs and VPQDs) not only exhibits tunable bandgap, moderate on/off current ratio, and good biodegradability, but shows enhanced stability and biosafety as well, allowing it to be a promising candidate for a variety of biomedical applications like antibacterial therapy, anticancer therapy, and biosensing and disease diagnosis. In this review, the classification and the relevant synthesis routes of VP are initially summarized, and the unique properties of VP nanomaterial momentous to its biomedical applications are subsequently expounded. The latest research advances of this emerging nanomaterial in the biomedical field are then introduced in detail, and both the existing challenges and future prospects are also discussed.