[Ultrasonic microbubbles for glioma-targeted drug delivery]

Ultrasonic microbubbles were used to open blood-brain barriers (BBB) with a reversed and limited behavior feature in the study, which could improve the brain-targeted delivery of anti-tumor drugs. The glioma rat model was prepared. Low-frequency ultrasound was combined with microbubbles to affect the permeability of BBB compared with the permeability of independently administered Evans blue (EB) crossing BBB. Time point and length of ultrasound were investigated whether they affect the permeability of BBB and the damage of brain tissue. The effect of the growth time of glioma on BBB permeability was explored. Only glioma had a very little impact on BBB permeability. However, ultrasonic microbubbles opened the BBB with the features of temporary, limited and reversed behavior and improved EB and magnetic resonance imaging contrast agent penetrating BBB. A length of 30 s ultrasound is appropriate for opening BBB and no damage of brain tissue. Drugs should be injected before ultrasound so that they enter into brain as BBB opening. Ultrasonic microbubbles can open BBB effectively and safely, which improve drugs penetrating BBB under proper time point and length.