Brain-Drug Delivery Through Intercellular Junction of Blood Brain Barrier (BBB) Using Cold Atmospheric Plasma

Abstract

To address the problems with brain drug delivery we aim to deliver the large molecular weight drug into the brain by opening intercellular junctions (e. g. tight junction) of blood brain barrier (BBB) using cold atmospheric plasma (CAP). The CAP produces reactive oxygen and nitrogen species (RONS) that include hydroxyl (HO^•), superoxide (O₂^•−), peroxyl (ROO^•), nitric oxide (NO^•), ozone (O₃), hydrogen peroxide (H₂O₂), and singlet oxygen (¹O₂). In this study, BBB cell model containing endothelial cells, pericytes and astrocytes was purchased from pharmaco-cell company Ltd. (Japan) and cultured using DMEM medium on 24-transwell plate. Upon confluency of the cells, fluorescein isothiocyanate dextran (FD-4) drug was added, and plasma was applied to the culture. The plasma Jet was prepared as follow (carrier gas: Argon, gas flow: 3 L/min, irradiation time: 60 s, irradiation distance: 20 mm, voltage: 2.2 k Pp., frequency: 10 kHz). After 1 h incubation at 37 ºC with 5% CO₂, trans-endothelial electrical resistance (TEER) was measured. The TEER value was reduced in plasma-treated cells compared to non-treated cells. It indicates that this plasma condition produced reactive species (RONS) that are involved in breaking proteins of intercellular junction. Because the lower the TEER value, the more permeability in the intercellular junction. FD-4 drug was added to the apical part (insert) of trans-well plate, and after plasma treatment with 1 h incubation, florescence intensity was measured from the basal side. The higher florescence intensity was detected in plasma treated cells compared to non-treated cells. This result may provide a valuable insight into a new strategy for brain drug delivery.