GPX4 and glioblastoma: At the same time, immunofluorescence staining was also used to investigate the effects of Fe3O4-siPD-L1@M-BV2 on the protein expression of GPX4 and PD-L1 in orthotopic drug-resistant GBM tissue, and the results were consistent with western blot experiment (Fig. 8C, Additional file 1: Fig. S14).