Nanostructured gold has been used in catalysis, opto-electronics, drug delivery, biosensing, and cancer therapy and there is growing demand to develop sterile, nontoxic, and environmentally safe methods for their synthesis. By tuning the structure of biocompatible molecules, such as the antioxidant rutin (vitamin P), Bikash K. Jena and colleagues, CSIR-Institute of Minerals and Materials Technology, India, have developed a new method for shaping Au nanostructures. The functional groups of biomolecules were used as stabilizing/reducing agents to avoid the need for seeds or surfactants, and played a vital role in shaping the structures.

Icosahedron-like nanostructured gold particles were formed easily at room temperature by using AuCl₄ and rutin. Slight changes in the concentration of rutin gave nanoparticles with different sizes and morphology – an increase gave spherical nanoparticles with a small size distribution, whereas low rutin concentrations led to particles of different shapes and varied sizes. Different nanoparticles were also formed by using catechol or quercetin as the reducing agent due to the side structures and functional groups present on the analogous ring of the biomolecule.

Because Au enhances electrocatalytic performance in the oxygen reduction reaction (ORR), the nanostructures obtained by using this biofriendly approach were also investigated for their activity and a shape-dependent electrocatalytic performance towards the reduction of oxygen was found.

• A Bioinspired Approach for Shaping Au Nanostructures: The Role of Biomolecule Structures in Shape Evolution,
  Subash C. Sahu, Aneeya K. Samantara, A. Ghosh, Bikash Jena,
  Chem. Eur. J. 2013.
  DOI: 10.1002/chem.201300268