Shuttle-mediated nanoparticle transport across an in vitro brain endothelium under flow conditions

The blood brain barrier (BBB) represents a challenge in the development of new nano‐delivery systems able to reach the central nervous system (CNS). In order to test the efficacy of these nanocarriers, it is fundamental to use in vitro models that resemble the in vivo cell culture conditions. Here, we demonstrate for the first time the ability of a membranotropic peptide, namely gH625, to transport a cargo—acting as a shuttle—across the BBB layer under flow conditions that mimic the blood flow rate. To this aim, a BBB microfluidic device was designed based on a transparent polyester porous membrane sandwiched between a top and a bottom overlying channel made of poly(methyl methacrylate) (PMMA). Our data clearly indicate that this microfluidic system allows the growth of brain endothelial bEnd.3 cells and the formation of a confluent layer at 7 days of culture that hinders the passage of nanoparticles compared to porous membrane alone. The device was validated at a 5 μL/min working flow rate, where the capability of the model to remain intact after nanoparticle passage was shown. Very interestingly, the decoration with the gH625 peptide enhances the adhesion of nanoparticles to the endothelial layer and the BBB crossing in flow conditions, thus confirming the efficacy of the gH625 as a delivery platform to the brain.