ALB and neoplasm: Liang et al. suggested NDs labeled by PEGylated denatured bovine serum albumin (BSA), and tumor vasculature-targeting tripeptides RGD, which is dcBSA-PEG-NDs, showed high efficiency in selectively targeting tumor sites in U-87 MG-bearing mice through the BBB [58]; in vitro BBB models revealed that the transcytosis mechanism and an additional direct cell–cell transport via tunneling nanotubes are both involved in this process [59].