The present application relates to the preparation method and application of the complex of the engineered
bacteria loaded with the functionalized
melanin nanosystem, which can effectively solve the problems of activating the STING pathway, reversing
T cell exhaustion, improving the effect of tumor
immunotherapy and ensuring the effect of
cancer treatment drugs, and the
melanin is prepared into
melanin nanoparticles, and the carboxylated melanin nanoparticles are formed through the
thiomalic acid reaction, the
polypeptide chain and 2-cyano-6-amino-
benzothiazole are modified at the carboxyl terminal of the melanin nanoparticles through the amidation reaction, the
metal ions are complexed on the surface of the functionalized melanin nanoparticles through the
metal complexation, and finally the functionalized melanin nanosystem is adhered to the surface of the engineered
escherichia coli through the adhesion, so as to obtain the complex of the engineered
bacteria loaded with the functionalized melanin nanosystem; the present application is convenient to operate, the method is stable and reliable, has good
biocompatibility and long
retention time, can play the multiple effects of targeting tumor, activating the cGAS-STING pathway, blocking the PD-1 / PD-L1 axis and reversing
T cell exhaustion.