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Thursday, 18 July 2013

Dual-Template Synthesis of nanoparticle superstructures

Publishing in Small, researchers from ICN2, ICMAB-CSIC and ETH describe long, wire-like superstructures of inorganic nanoparticles fabricated using silver-peptide belt-like templates.

Researchers from ICN2, together with colleagues from the Institute of Materials Science of Barcelona (ICMAB-CSIC) and the Swiss Federal Institute of Technology (ETH), in Zurich, have just published an article in Small describing a new class of wire-like superstructures comprising nanoparticles of one or more types. The article, entitled ""Dual-Template" Synthesis of One-Dimensional Conductive Nanoparticle Superstructures from Coordination Metal–Peptide Polymer Crystals", showcases the team's Dual Template Synthesis of the nanoparticle wires, using belt-like templates of silver-tripeptide crystals. The work was led by ICN2 Group Leader and ICREA Research Professor Dr Daniel Maspoch, Ramón y Cajal Researcher Dr Inhar Imaz and doctoral student Marta Rubio, of ICN2's NANOup Research Group.

The researchers first created a new class of metal-peptide scaffolds based on silver (I) and the tripeptide aspartic acid-leucine-leucine (DLL). They exploited both the ease with which silver (I) can be thermally reduced into metallic silver, and the self-assembly and recognition properties of the peptide molecules to guide self-assembly processes, in order to selectively create layers of inorganic nanoparticles on the outside and subsequently, on the inside, of the templates.

one type on the outside, and the same or a different type on the inside), including Ag@Ag and Fe3O4@Ag wires (length: ca. 2 to 250 ?m; width: ca. 50 nm to 2 ?m; nanoparticle diameter: ca. 20 to 40 nm).

Having optimised the synthetic parameters and demonstrated the feasibility and scope of their approach, Dr Maspoch and colleagues also explored the electrical conductivity of their wire-like superstructures, finding that their Dual-Template Synthesis approach allows the preparation of very long conductive wires without defects. Their work also included patterning of Ag@Ag wires onto platinum electrodes for geometric measurements on the conductivity of longitudinal sections. They also confirmed both the magnetic behaviour and the electrical conductivity of their Fe3O4@Ag wires, concluding that the template synthesis did not compromise the Fe3O4 nanoparticles and therefore, did not affect their magnetism.

The researchers are confident that their Dual Template Synthesis approach will enable the synthesis of superstructures of diverse metallic nanoparticles, including those of zinc, iron, indium, gadolinium and their corresponding oxides.

To read the article ""Dual-Template" Synthesis of One-Dimensional Conductive Nanoparticle Superstructures from Coordination Metal–Peptide Polymer Crystals", click here.