Shear-Activated Nanotherapeutics for Drug Targeting to Obstructed Blood Vessels

Bio-Inspired Drug Delivery Noting that platelets naturally migrate to narrowed blood vessels characterized by high fluid shear stress, Korin et al. (p. 738 , published online 5 July; see the Perspective by Lavik and Ustin ) developed a nanoparticle-based therapeutic that uses a similar targeting mechanism to deliver a drug to vessels obstructed by blood clots. Aggregates of nanoparticles coated with the clot-dissolving drug tPA (tissue plasminogen activator) were designed to fall apart and release the drug only when encountering high fluid shear stress. In preclinical models, the bio-inspired therapeutic dissolved clots and restored normal blood flow at lower doses than free tPA, suggesting that this localized delivery system may help reduce the risk of side effects such as excessive bleeding.