With the aim to improve local cancer radiotherapy,this work reports the fabrication of alginate (Alg) scaffolds containingbovine serum albumin (BSA)-coated bismuth sulfide (Bi2S3@BSA) nanoradiosensitizers using three-dimensional (3D) printing.Under single-dose X-ray irradiation in vitro, Alg-Bi2S3@BSA scaffolds significantly increase the formation of reactiveoxygen species, enhance the inhibition of breast cancer cells, andsuppress their colony formation capacity. The gene discussed is ALB; the disease is breast carcinoma.