Polypeptide nanocarrier and preparation method and application thereof

The invention relates to the technical field of medicines, and particularly relates to a polypeptide nanocarrier and a preparation method and an application thereof. The polypeptide-constructed nanocarrier provided by the invention includes a short peptide consisting of alanine, glycine and the like, and cholesterol. A polypeptide formed in the invention can be degraded naturally in a cell; multiple amino acids in the polypeptide are all amino acids present in a body, and have no toxicity or side effect to the cell and the human body; a cell proliferation test with a CCK-8 method indicates that the prepared nanocarrier has a very low cytotoxicity, and meanwhile has a good capacity for co-delivery of a gene and an insoluble compound; and the nanocarrier of the invention can specifically target a tumor cell in immunotherapy of a breast cancer, deliver an immune checkpoint blocking agent, promote an own anti-tumor immunity, and promote apoptosis of a breast cancer cell, thus becoming a targeting, effective and l