The Laser Technologies of Targeted Opening of Blood-Brain Barrier for Drug Brain Delivery

Here we show the photodynamic treatment (PDT) causes significant increase in the permeability of the blood-brain barrier (BBB) in healthy mice. Using different doses of laser (635 nm, 10-40 J/cm
²
) and photosensitizer (5-aminole-vulinic acid - 5-ALA, 20 and 80 mg/kg, i.v.), we found the optimal PDT for the reversible opening of BBB that is 15 J/cm
²
and 5-ALA, 20 mg/kg, when the brain tissues recover 3 days later. Further increase in the laser or 5-ALA doses has not amplifying effect on the BBB but associated with severe damages of brain tissues. These results can be good informative platform for the further studies of new strategies in brain drug delivery and for the better understanding of mechanisms underlying cerebrovascular effects of PD-related fluorescence guided resection of brain tumor.