The invention belongs to the technical field of
probiotic preparations, and particularly relates to engineered probiotics loaded with Cu2-xSe nanoparticles in cells as well as a preparation method and application of the engineered probiotics. According to the application, the non-toxic probiotics are used as a
bioreactor, and the engineered probiotics which are good in stability and have excellent photo-thermal performance and H2O2
catalysis performance and are loaded with the Cu2-xSe nanoparticles in cells are successfully constructed by regulating and controlling incubation conditions of the probiotics, the
copper source and the
selenium source. The compound can enrich tumor sites in a targeted manner, is efficiently taken by
tumor cells, kills the
tumor cells, induces M2 type TAMs to be reversely polarized into M1 type TAMs, improves inhibitory TIME, promotes TDLNs and DCs in TME to be mature, increases infiltration of CD8 +
effector T cells and the number of CD8 + T cells and central memory T cells in the
spleen, and achieves the anti-tumor effect. In addition, the long-term immune
memory effect can be induced to be generated, and
tumor recurrence is effectively inhibited.