Figure 3
The brain-targeting property of AuNPs after fabrication with neuron-targeted exosome. (a) Schematic diagram showing the arrangement of the flow chamber perfusion system. The instrument required brain cells cultured on a tissue culture plate. A flow chamber was then assembled over the cultured cells and targeted exosome-coated AuNPs were flowed over the cultured cells. (b) Adhesion of nanoparticles to brain cells under flow conditions. Brain cells were exposed to targeted exosome-coated AuNPs or control AuNPs under flow condition. Hela cells were used as negative controls. As nanoparticles had been fluorescently labelled, the binding of nanoparticles to cells was visualized and analyzed using fluorescence microscopy. (c) An in vitro blood-brain barrier (BBB) model being composed of co-culture with endothelial (bEnd.3) and astrocyte-like (ALT) cells was established to evaluate the transcytosis of AuNPs coated with RVG- or unmodified exosomes. The expression of tight junction protein claudin-5 and ZO-1 in BBB model (Supplementary S2). Green: claudin-5 proteins; Blue: cell nucleus. (d) The percentage of exosome-coating AuNPs transported across the BBB over 20 hr. targeted exosome-coated AuNPs or control AuNPs were added to the apical chamber and incubated at 37 °C up to 24 hr. Signals of fluorescently labelled nanoparticles in the basal chamber were measured in 0.5 ml aliquots at different time points.
