The exosomes are nano extracellular vesicles generated by cells, which can be used as natural drug carriers. Compared with the widely used nano carriers, they have the advantages of nano size, biodegradability, non-toxic, endogenous, low immunogenicity, strong cargo carrying capacity, and can cross the blood brain barrier. In the face of brain glioma with high mortality and easy recurrence, how should chemotherapy drugs break through the blood brain barrier, directly reach the focus and accurately target tumor cells? Recently, Cheng Guosheng, a research team of Suzhou Institute of Nanotechnology and Nanobionics, Chinese Academy of Sciences (hereinafter referred to as Suzhou Institute of Nanotechnology, Chinese Academy of Sciences), designed and developed an engineered exocrine body that can be loaded with chemotherapy drugs to penetrate the blood-brain barrier, and can simultaneously target the endothelial cell surface and glioma cells in the brain used for the blood-brain barrier. Relevant research papers were published in the Journal of Extracellular Vesicles. In recent years, the research in the field of exosomes has continued to heat up, which is the "new favorite" of major biological enterprises and investors, especially in the engineering transformation of exosomes, which is almost "a blue ocean". The new engineering drug loaded exosomes developed by Cheng Guosheng's team can improve the targeting of tumor focus areas, thereby improving the concentration of therapeutic drugs in the focus areas, so as to achieve the best therapeutic effect, This provides a new perspective and new idea for the treatment of central nervous system diseases by engineering the exocrine body. Two kinds of barriers prevent chemotherapy drugs from reaching the focus glioma refers to tumors originating from brain glial cells, which are the most common primary intracranial tumors. The annual incidence rate of gliomas in China ranges from 5 to 8 per 100000. The five-year mortality rate is second only to pancreatic cancer and lung cancer in the whole body tumors, which causes great harm to human life and health. At present, surgical resection is the main treatment for glioma. However, due to the high invasiveness, rapid growth and enhanced angiogenesis of the tumor, glioma cannot be removed completely by conventional surgery, resulting in poor prognosis and short survival time. In order to effectively inhibit tumor growth and prolong the survival period of patients, chemotherapy has become one of the most important means to treat glioma after surgical resection. However, if chemotherapy drugs want to reach glioma cells directly, they have to face two natural biological barriers, namely blood brain barrier and blood brain tumor barrier. "These two barriers seriously hindered the passage of chemotherapy drugs, especially the blood brain barrier, which almost prevented all macromolecules and 98% small molecules from entering the brain tumor region, greatly weakening the effect of chemotherapy." Introduction by Zhu Zhanyi, a team member and doctoral candidate of Suzhou Institute of Nanotechnology, Chinese Academy of Sciences. In addition, most traditional anti-cancer drugs have strong biological toxicity. What scientists need to solve is not only to deliver chemotherapy drugs to the lesions, but also to reduce their biological toxicity to the human body in the process of transportation. These are problems that need to be solved urgently in the drug delivery system. Exosomes have the potential to act as drug "couriers". Large exosomes are nano extracellular vesicles generated by cells, with a size of 30-150 nm. They are rich in proteins, nucleic acids, lipids and other bioactive components from parent cells, and play an important role in intercellular signal transmission. However, when exosomes were discovered in the 1980s, it was recognized that