DNA-controlled dynamic colloidal nanoparticle systems for mediating cellular interaction

Dynamic DNA clustering of nanoparticles The size and shape of nanoparticles can increase the cellular uptake and delivery of contrast agents and therapeutics. Ohta et al. created gold nanoparticles partly covered with DNA chains and with folic acid as the targeting molecule (see the Perspective by Parak). The particles could link together to hide the folic acid or to expose it on the surface, depending on the hybridization and overall particle configuration. The addition of complementary DNA allowed switching between structures, thus changing the way the particles interacted with cells. Science , this issue p. 841 ; see also p. 814