CD47 and neoplasm: In another immunotherapeutically inclined design, Guo et al. (2019) addressed the “don't eat me” signal employed by cancer cells by engineering PEGylated bismuth selenide nanoparticles conjugated with anti-CD47 antibodies (Ab-PEG-Bi2Se3).67 These particles effectively blocked the interaction between tumor-expressed CD47 and macrophage SIRPα, enhancing phagocytic activity.