The enzyme-linked immunosorbent assay (ELISA) results revealed that the Tet-HER1-CAR-T cells activated by Doxy and Doxy@CaCO3-PEG in the presence of HER1-overexpressing TNBC (MDA-MB-468) and lung cancer (NCI-H23) cells effectively secreted IL-2, IFN-γ and TNF-α at comparable levels (Fig. 2G–I and Fig. S6A–C). Here, IFNG is linked to lung cancer.