Fig. 8.

In vitro crossing of the BBB & in vivo tumor-targeting imaging. a The in vitro transcytosis experiment was performed to assess the abilities of HFn and 2D-HFn to cross the BBB. Briefly, bEnd.3 mouse brain endothelial cells were cultured in the upper chamber of a Boyden chamber to mimic the BBB. U-87MG cells were cultured in a 6-well plate. FITC, FITC-HFn, or FITC-2D-HFn was added into the medium of the upper chamber. After four hours of incubation, the U-87MG cells were harvested, and the FITC signal was analyzed by flow cytometry. No signal was detected in the FITC group. Approximately 29.4% of the cells were FITC-positive in the FITC-HFn group, indicating that FITC-HFn crossed the bEnd.3 cell layers and bound to U-87MG cells. In comparison, 59.2% of the cells were FITC-positive in the FITC-2D-HFn group, approximately two-fold greater than that of the FITC-HFn group. b 2D-HFn had a strong tumor-targeting capability in an orthotopic tumor model. IRDye800-2D-HFn was iv injected into the orthotopic U-87MG tumor model mice, and the tumor volume and location of IRDye800-2D-HFn were analyzed by MRI and IVIS imaging, respectively