cis-Pt Mediated Assembly of Gold Nanoparticles on DNA

Utilizing peptide-anchored DNA templates for novel programmable nanoparticle assemblies in biological macromolecules: A review

Biological macromolecules such as proteins and DNA are known to self-assemble into various structural moieties with distinct functions. While nucleic acids are the structural building blocks, peptides exemplify diversity as tailorable biochemical units. Thus, combining the scaffold properties of the biomacromolecule DNA and the functionality of peptides could evolve into a powerful method to obtain tailorable nano assemblies. In this review, we discuss the assembly of non-DNA-coated colloidal NPs on DNA/peptide templates using functional anchors. We begin with strategies for directly attaching metallic NPs to DNA templates to ascertain the functional role of DNA as a scaffold. Followed by methods to assemble peptides onto DNA templates to emphasize the functional versatility of biologically abundant DNA-binding peptides. Next, we focus on studies corroborating peptide self-assembling into macromolecular templates onto which NPs can attach to emphasize the properties of NP-binding peptides. Finally, we discuss the assembly of NPs on a DNA template with a focus on the bifunctional DNA-binding peptides with NP-binding affinity (peptide anchors). This review aims to highlight the immense potential of combining the functional power of DNA scaffolds and tailorable functionalities of peptides for NP assembly and the need to utilize them effectively to obtain tailorable hierarchical NP assemblies.

On the application potential of gold nanoparticles in nanoelectronics and biomedicine

Ligand-stabilized gold nanoparticles (AuNPs) are of high interest to research dedicated to future technologies such as nanoelectronics or biomedical applications. This research interest arises from the unique size-dependent properties such as surface plasmon resonance or Coulomb charging effects. It is shown here how the unique properties of individual AuNPs and AuNP assemblies can be used to create new functional materials for applications in a technical or biological environment. While the term technical environment focuses on the potential use of AuNPs as subunits in nanoelectronic devices, the term biological environment addresses issues of toxicity and novel concepts of controlling biomolecular reactions on the surface of AuNPs.

In situ investigation of Pt(100--x)Au(x) and Pt(100--y)Sn(y) nanoalloys

Dispersed sols of 1-10 nm sized Pt(100--x)Au(x) and Pt(100--y)Sn(y) nanoalloys have been prepared separately at various x and y above and below the miscibility limit in the bulk metals. Pt(100--x)Au(x) was derived from trisodium citrate reduction of aqueous solutions of H2PtCl6 and HAuCl4. Pt(100--y)-Sn(y) was produced by (i) complexing Sn2+ with glucose at 323 K at pH > 7, (ii) neutralising this with H2PtC16 addition and (iii) reducing the bimetallic precursor with glucose on raising the temperature to 373 K. For Pt(100--x)Au(x (where both metals were zero-valent) as x increased the average size of nanoalloy particles increased. These particles adsorbed onto graphite, where the extent of hydrogen chemisorption at 298 K decreased by 67% at 9 at % Au. Pt/SnO2 nanoparticles (<3 nm in size) were adsorbed onto alumina. The Pt interacted with and catalysed the reduction of SnO2, with some Pt(100--y)Sn(y) nanoalloy formation at about 673 K which even in the bulk occurs over a wider range of compositions than Pt-Au) and enhanced H2 chemisorption at 17-33 at % Sn. Nevertheless some Sn must remain in a positive oxidation state on the alumina surface. The ratio of rates of 2MP/ 3MP formation from MCP and n-hexane may be informative in chemically fingerprinting (and revealing fundamental differences in) these nanoalloy surfaces. The reasons for this are seen in terms of the surface structures on these two types of nanoalloy particles (i.e. the availability of contiguous asymmetric pairs of active surface atoms *, which, as expected, is found to pass through a maximum or decrease beyond specific values of x and y).