Fig. 4

Blood-brain barrier (BBB) permeability was increased under surface acoustic waves (SAW) treatment. A A transwell model was constructed to imitate the BBB in vitro. Transwell contains an insert which hanged in the well plate. The bottom of transwell insert was microporous membrane that separates the well plate into two sides. The apical side (up chamber) mimicked the bloodstream, while the basolateral side (low chamber) mimicked the brain. Human brain microvascular endothelial cells (hBMECs) were seed and reached confluence to form the in vitro BBB model. After SAW treatment, the change of transendothelial electrical resistance (TEER) and transendothelial permeability of chemical reagent could be measured. B hBMECs were seeded into transwell for 24 h to form the preliminary BBB and then exposed to SAW in 19.68 MHz for 5 min at 20 dBm, 25 dBm and 30 dBm, respectively. The TEER was measured with endohm tissue resistance measurement chamber at the indicated time points. The -1 h represented the initial TEER was measured at 1 h before SAW exposure. Data are representative results of two independent experiments (time point 0 h represented the 24 h incubation of transwell inserts). C The BBB was treated with a 19.68 MHz SAW at 30 dBm for 1 min, 3 min, and 5 min, respectively. The TEER was detected at the indicated time points. The data are representative of three independent experiment and displayed as means ± SEM (time point 0 h represented the 24 h incubation of transwell inserts). D hBMECs were seeded in transwell, then the BBB was exposed on various power of SAW. The change of TEER was measured immediately. The data is representative of three independent experiment. Data are shown as means ± SEM. **, p < 0.01, ***, p < 0.001