Currently, there is no effective treatment for glioblastoma multiforme (GBM), the most frequent and malignant type of brain tumor. Some low molecular weight antitumor agents are used to permeate the gaps between endothelial cells in the BBTB (blood−brain tumor barrier), which is a characteristic blood vessel structure and formed by the partial collapse of the blood−brain barrier, but they are rapidly excreted from the kidneys, resulting in low GBM accumulation.
