Fig. 2

a Diagram of a core–shell NP. b TEM image of monodispersed spherical particles. c Time course of ZnO-binding peptide association with NPs in cell culture medium. d Intracellular NPs visualized by DAB-enhanced Prussian blue staining of DCs labeled with 100 mg/mL Fe₃O₄ NPs or Fe₃O₄–ZnO NPs after incubation for the indicated time. e In vivo MRI images of (left) draining lymph nodes of a mouse injected with DCs labeled with Fe₃O₄–ZnO (red arrowhead) or ZnO NPs (yellow arrowhead) into the ipsilateral footpads. Right shows a draining lymph node (green arrowhead) of a mouse injected with cell-free Fe₃O₄–ZnO NPs. f Representative immunohistochemistry of draining lymph nodes after injection with Fe₃O₄–ZnO NP-labeled DCs (dark brown dots). T, T cell zone (Thy1.2⁺); B, B cell follicle (B220⁺). g CEA-specific, IFN-γ⁺ CD8⁺ T cell responses of mice immunized with DCs. h, i Tumor volume of C57BL/6 mice (h) and CEA–transgenic C57BL/6 mice (i) injected with MC38/CEA cells. j Survival rate of mice injected with MC38/CEA cells. Data are expressed as means ± SD; *P < 0.05 [67].