The invention relates to the technical field of nano-materials, in particular to a polypeptide nano-material for binding HER2 and a preparation method and application thereof, the polypeptide nano-material comprises polypeptide with an
amino acid sequence as shown in SEQ ID NO: 1 and an I-type
photosensitizer connected with the last
amino acid of the polypeptide; the polypeptide comprises a ligand unit and a
fiber deformation element; the I-type
photosensitizer is connected to one end, deviating from the ligand unit, of the
fiber deformation element, and the I-type
photosensitizer has the aggregation-induced emission characteristic. The polypeptide nano-material can be self-assembled in an
aqueous solution through hydrophilic and hydrophobic effects to form spherical nano-particles, the spherical nano-particles are disintegrated through ligand-
receptor interaction induction, and an ordered, stable and continuous beta-folding structure is formed through a pi-pi accumulation effect and a
hydrogen bond, so that the polypeptide nano-material is converted into a
nanofiber network structure in situ in a tumor, and the tumor activity is improved. The type and intensity of
active oxygen generated by the I-type photosensitizer with AIE characteristics can be remarkably improved, and finally, specific efficient
photodynamic therapy of HER2 positive
breast cancer is realized.