Fig. 9. Magnetic field enhanced anti-cancer effects of M-MZNs-DOX in H22 tumor bearing mice. (A) Tumor volume curve of mice treated with (control) saline, M-MZNs-PEG, DOX, M-MZNs-DOX (M−) in the absence and (M+) presence of magnetic field after 4 times of intravenous injection. (B) Photographs of tumors excised from mice after treatments. (C) Changes in body weights of mice in the five groups during treatment. (D) Tumor apoptosis analysis and (E) histological images of tumor slices from mice in the five groups with standard TUNEL staining. Scale bars represent 50 μm.