The purpose of this research was to develop and evaluate a nanocomposite material for the treatment of colorectal cancer.The nanocomposite consisted of manganese-doped silver nanoparticles coated with silica (Si-Ag: Mn3O4).The nanocomposite was synthesized by co-precipitating silver and manganese oxide, followed by a silica coating using the Stober method.Extensive characterization was conducted to assess the morphol., optical, and stability properties.The key findings of this study are the Si-Ag: Mn3O4 nanocomposite exhibited unexpected and potent cytotoxicity against colorectal cancer cells, exceeding the effects of the pos. control, cisplatin.The silica coating increased the Ag: Mn ratio, further enhancing the efficacy of the nanocomposite in cancer treatment; the nanocomposite maintained cellular mobility without agglomeration or sedimentation, indicating its potential for targeted tumor destruction; and gamma irradiation of the nanocomposite further increased its cytotoxic effects on colorectal cancer cells.In conclusion, the unique combination of silver, manganese oxide, and silica in this nanocomposite framework shows great promise for advanced applications in selective cancer therapy.The nanocomposite demonstrated significant cytotoxicity against HT-29 colorectal cancer cells, particularly at a gamma dose of 5.256 kGy.The results of this study open new perspectives in biol. research, cancer treatment, and nanomedicine.