Nanoparticles hit tumors with one-two punch

Nature : Sangeeta Bhatia of MIT and colleagues have designed two different types of cancer-fighting nanoparticles to work in tandem and piggyback on the body’s rapid response to clotting, writes Nature‘s Corie Lok. Bhatia’s team created a scout particle to fit through the abnormally large pores in a tumor’s blood vessels; when near-IR light is shone on the scout particles, they heat up just enough to damage the tumor and trigger a rapidly escalating molecular response known as the clotting cascade. The drug-bearing nanoparticle has a protein on its surface that is a substrate for an enzyme called factor XIII, which crosslinks fibrin at the end of the cascade; the particles are attracted as the clotting process occurs. Factor XIII crosslinks the nanoparticles’ protein to the fibrin in the clot, and the particles then deliver the drug. The factor XIII and fibrin generated during the clotting process create additional binding sites for the particles; that process leads to a 40-fold increase in the amount of drug delivered compared with drug-delivering nanoparticles already in use.