Recently, Yu Xuefeng, a researcher at the Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, and Zhang Han, a professor at Shenzhen University, and Zhu Jianhao, a professor from Hong Kong City University, successfully prepared a biodegradable photothermal conversion material based on black phosphorus for efficient and safe tumor photothermal conversion treatment. Nano-photothermal therapy has the advantages of wide application range, non-invasiveness, strong selectivity, simple procedure and low damage to normal tissues. It has shown great value in the fields of tumor therapy, drug controlled release and light-controlled implant materials. However, the commonly used inorganic nano-photothermal conversion materials in the body often can not be degraded, but exist in the form of nano-particles in the organism for a long time, or the material degradation products contain toxic substances, which will lead to the potential toxicity of the body, which As a result, it is difficult for them to obtain the approval of international medical auditing agencies (such as the FDA) and enter into practical clinical applications. Research and development of superior performance and biodegradable nanomaterials, the key to the practical application of nano-technology and difficult. Black phosphorus is a direct bandgap semiconductor material with a two-dimensional layered structure, which has drawn much attention in recent years, and exhibits excellent electrical and optical characteristics. In previous research, Yu Xuefeng's team found that black phosphorous quantum dots of only a few nanometers in size have high near-infrared photothermal conversion capacity (Angew. Chem. Int. Ed. 2015, 54, 11526). Further, black phosphorus is oxidized under the physiological environment to decompose into small molecule products such as phosphate ions and phosphite ions (Angew. Chem. Int. Ed. 2016, 55, 5003). However, recent studies have found that bare black phosphorus degradation in physiological environment too fast, will lead to its optical properties in the body during the cycle of decline, thus affecting the photothermal effect of treatment. In response to this problem, the research team used emulsification solvent evaporation method to prepare a polymer-polymer (PLGA) core-shell structured nanosphere (BPQDs / PLGA) encapsulating black phosphorus quantum dots (BPQDs) Degradable hydrophobic biomedical polymer, the polymer shell formed by the internal black phosphorus quantum dots can be isolated from the physiological environment, to ensure that the black phosphorous quantum dots during the treatment of stable performance. After the photothermal therapy is over, the black phosphorous quantum dots will be slowly released and degraded with the gradual degradation of the PLGA shell, and then be safely metabolized out of the body. Cell and animal experiments have shown that BPQDs / PLGA has good biosafety and tumor passive targeting, and shows high photothermal therapy efficiency, the implementation of five minutes of near infrared light can effectively kill the tumor . The successful development of this new type of biodegradable photothermal conversion material undoubtedly can promote the actual clinical application of photothermal therapy technology and provide guidance and reference for the future biomedical applications of nanomaterials. The research team has applied for the relevant invention patents and is actively promoting the declaration of the relevant clinical application permits for its early clinical application.