Fig. 4.

Carrier flexibility modulates engagement of targeted carriers with caveolar plasmalemma vesicle associated protein (PLVAP) in lung endothelium. Carrier mechanical properties can affect how well carriers access targets (e.g. by soft particles “squeezing” into small spaces, as depicted in (a)). PLVAP is located in a sterically concealed position, the caveolar neck, in lung endothelial cells. Soft dextran particles (a) were able to target PLVAP more effectively than crosslinked dextran particles (b) or rigid polystyrene particles (c) of similar size. As evaluated in radioisotope tracing (d) and fluorescence (e) studies, PLVAP targeting efficacy in the lungs decreased as nanoparticle Young's modulus (as determined by AFM) increased (d). Adapted from [131,228].