The reporter learned from Hainan University that Professor Wang Chaohui from the School of Biomedical Engineering at the university has designed an implantable microneedle patch that can sustainably act on residual tumors after surgery and convert it into an in situ tumor vaccine, activating specific anti-tumor immune responses to inhibit tumor recurrence and metastasis. The relevant research results were recently published in the international academic journal Advanced Medical Materials. Due to the high invasiveness of tumors, it is very difficult to completely remove them through surgery, and residual tumors can easily cause tumor recurrence and metastasis. Patients usually need two weeks to recover before receiving postoperative chemotherapy, and their body is in an immunosuppressive state after surgery, which provides opportunities for residual tumor growth and metastasis. Therefore, timely treatment of residual tumors after surgery is of great significance for improving the postoperative survival rate of patients. Wang Chaohui introduced that this "postoperative ready to use" microneedle patch is loaded with semiconductor nanocrystals that can respond to chemical signals in the tumor microenvironment. Micro needle patches continuously induce immunogenic cell death of tumor cells through the catalytic effect of in situ nanoenzymes, thereby enabling immune cells to effectively recognize, kill, and remember tumor cells. Using the mouse breast cancer model, the researchers confirmed that the patch could significantly reduce the tumor recurrence rate, activate the immune memory effect of the mouse, and resist the distal tumor by acting on the residual tumor of the mouse. Meanwhile, due to the fact that implantable microneedle patches only load biocompatible nanocrystals, which facilitate homogenization preparation, their postoperative application is very convenient and has strong conversion potential, providing a new "connection" method for tumor surgery and chemotherapy. (Lai Xin She)