have been already applied for the restoration. [2] During the development of the treatments, the term "tissue engineering" was advanced in the 1980s, in which the biological and engineering principles are combined to fabricate functional replacements for regenerating injured tissues. [3] However, the classical tissue engineering strategy needs a lot of time and much laborious effort for extensive cell expansion steps. In the past few decades, a new idea, known as in situ tissue regeneration (ISTR), was introduced. ISTR means that the host endogenous stem cells or tissuespecific progenitor cells are guided to the location of trauma for tissue recovery in vivo by implanting specific biomaterials system without complicated in vitro manipulation. [4] Many biomaterials, including natural biomaterials, [5] synthetic biopolymers, [6] and bioceramics, [7] have been widely applied for ISTR. The degradation rate of materials is crucial to the successful ISTR, as a rapid degradation may influence the properties of implanted biomaterial composites, for example, causing a mechanical failure. From the other side, if the composite degrades too sluggishly, an inflammation might occur and impair the recovery of damaged tissue. [8] Along with the rapid development of nanomaterials, the 2D materials [9] have attracted ever-increasing interest in tissue regeneration, owing to their remarkable optical properties, biocompatibility, large specific surface area, and high payload of drugs and agents. However, the ISTR application area is limited by the poor biodegradability of conventional 2D nanomaterials. Attributed to the excellent biodegradation ability, 2D black phosphorus (BP) has stepped into people's horizon, which shows more promising potentials in organism restoration over other 2D materials. The bulk form of BP was first synthesized by Bridgman in 1914 from white phosphorus with a high-pressure synthesis method. [10] Nevertheless, the BP crystal did not gain much attention due to the small band gap and the difficulty of controlling the material quality, [11] until a monolayer (ML) of BP crystal was introduced by several research groups in 2014. [12] The 2D nanomaterial of BP, also known as phosphorene, has several different properties from other 2D materials, e.g., graphene. One different major point is that the lone pair electron makes phosphorus atom be an active chemical adsorption position for oxygen molecules. With the rapid increase of BP surface, phosphorene will chemically decompose very quickly Nanomaterials have attracted ever-increasing interest in tissue regeneration in the past few decades. As an emerging 2D layered nanomaterial, black phosphorus shows more promising potentials in organism restoration than other 2D materials, attributed to its extraordinary biodegradation ability, remarkable optical properties, and high payload of drugs and agents. The degradation products, i.e., phosphate, can be adsorbed by tissues for specific regeneration such as bone, yet the excessive degradation rate of black phosphorus wil...