Fig. 6

Distribution and pharmacokinetics of Fe₃O₄-siPD-L1@M_-BV2 in orthotopic drug-resistant GBM mice. A The distribution of Fe₃O₄-siPD-L1@M_-BV2 in orthotopic drug-resistant GBM mice observed by in vivo bioluminescence imaging. B The integrated brain targeting efficiency of Fe₃O₄-siPD-L1@M_-BV2. C Distribution of Fe₃O₄-siPD-L1@M_-BV2 in orthotopic drug-resistant GBM tissue observed by LSCM. CD31 staining: green color (stands for blood vessel). Cy5 staining: red color (stands for nanoparticle). T: tumor tissue; N: normal tissue. D Plasma siPD-L1 concentration–time curve in orthotopic drug-resistant GBM mice. E The content of siPD-L1 in orthotopic drug-resistant GBM tissue. F The content of siPD-L1 in normal brain tissue. G The siPD-L1 content ratio between in GBM tissue and in normal brain tissue. H The intracellular level of siPD-L1 in orthotopic drug-resistant GBM tissue. I The extracellular level of siPD-L1 in orthotopic drug-resistant GBM tissue. J The ratio of siPD-L1 content between in intracellular and in extracellular. K The intracellular Fe²⁺ level in orthotopic drug-resistant GBM tissue at 12 h after drug administration. (n = 3, mean ± SD, ^*P < 0.05, ^**P < 0.01, ns: no significant difference)