RNA-Mediated Synthesis of Palladium Nanoparticles on Au Surfaces

Abstract

RNA catalysts for the shape-controlled synthesis of Pd particles from the precursor complex trisdibenzylideneacetone dipalladium ([Pd2(DBA)3] were recently discovered in our laboratory (J. Am. Chem. Soc. 2005, 127, 17814-17818). In the work described here, RNA codes for hexagonal Pd platelets and Pd cubes were covalently immobilized on gold surfaces and evaluated for their activity toward particle synthesis. When coupled to gold via oligoethylene glycol linkers, both RNA sequences were able to catalyze the formation of Pd particles with the same shape control previously observed in solution. For low surface coverages, the average distance between RNA molecules on the surface was estimated at ca. 300 nm, yet large (e.g., dimensions of hundreds of nanometers) Pd hexagons and cubes still formed. This surprising result suggests that a single RNA molecule may be sufficient for nucleating and controlling the shapes of these particles. Finally, the use of surface-bound RNA as a tool for directing the orthogonal synthesis of materials on surfaces was demonstrated. Patterning the RNA code for Pd hexagons next to the code for Pd cubes, followed by incubation in a solution containing [Pd2(DBA)3], resulted in the spontaneous formation of spatially distinct spots of hexagonal and cubic particles.

Formation of palladium(0) nanoparticles at microbial surfaces

“…The development of methods for the synthesis of metal nanoparticles of a defined size and shape has emerged as a new field in nanotechnology (e.g., Artuso et al, 2003; Beck et al, 2000; Cha et al, 2007; Fan et al, 2008; Lu et al, 2001; Nadagouda and Varma, 2006). The use of natural or artificial membrane entities may offer a novel approach for generating size‐controlled metal nanoclusters, as reported with other highly structured biomolecules (Feldheim and Eaton, 2007; Gugliotti et al, 2004, 2005; Liu et al, 2006).…”

The dawn of the RNA World: Toward functional complexity through ligation of random RNA oligomers

“…A fraction of either the short original modules (e.g., some stem-loops) or the ligated products could have shown aptamer activities allowing a tighter binding to the mineral surface, and therefore increasing the ratio of surface-bound versus in-solution molecule. Although not experimentally observed yet, the likely existence of RNA aptamers with mineral-binding activity is supported by the possibility to select in vitro active RNA molecules with enhanced metal binding affinity (Gugliotti et al 2004;Liu et al 2006). Also, additional metal or mineral-binding RNAs could be discovered since a growing number of RNA aptamers, usually 12-60 nt long, are currently selected against many organic and inorganic ligands (Stoltenburg et al 2007).…”

Base-Directed Formation of Fluorescent Silver Clusters

“…13,14 Nucleic acids are distinguished from other ligands because they can form and stabilize the nanoparticles as well as assemble more complex nanomaterials via base pairing interactions. 14,15,16 Our work utilizes DNA as a scaffold for the synthesis of silver clusters composed of 2-10 atoms. Earlier studies were motivated by the sequence specificity of the interaction of silver clusters with cytosine, and recent studies emphasize the key role of this and other bases for the formation of a range of clusters with distinctive fluorescence spectra.…”