Another innovative strategy was proposed by Huo et al. Exploiting the high Tf concentration in the blood and the upregulation of Tf receptors in both brain endothelial and GBM cells, covalent organic framework nanospheres, composed of PEI-coated mesoporous silica nanospheres, were decorated with the peptide T10, which has a high affinity to Tf. Here, TF is linked to glioblastoma.