Programmed ripening of nanoparticles using a DNA template

Nanoparticle (NP) ripening is a process where energetically favored larger 8 particles grow at the expense of smaller ones: while important in NP synthesis, it is often difficult to control during NP applications. Here, we unveil a new Contact-dependent, Localized Galvanic Ripening (CLGR) mechanism that enables precise control of NP ripening in solution. As neighboring silver NPs on a DNA origami template grow homogeneously to the point of making contact, the subtle size-dependent electrochemical potential differences of the NPs promote one silver shell to erode and redeposit locally onto the adjacent NP, leading to asymmetric structures. The unique on/off control through NP contact in CLGR presents a strategy to program the erosion and growth of specific NPs in a construct, which we exploit to synthesize customized heterogeneous core-shell NP structures with pre-designed plasmonic properties. CLGR is an essential phenomenon to consider for future nanodevice and nanophotonics designs.