Nanoscale & Nanoscale Advances Blog

New Nanoscale communication

Mechanically interlocked gold and silver nanoparticles using metallosupramolecular catenane chemistry

Carl A. Otter, Philipus J. Patty, Martin A. K. Williams, Mark R. Waterland and Shane G. Telfer

Nanoscale, DOI: 10.1039/c0nr00801j

A specially designed metallosupramolecular linker has been used to ‘interlock’ gold and silver nanoparticles into aggregate assemblies. Waterland, Tefler and coworkers at Massey University in New Zealand used a PEGthiol-functionalised bis(phenanthroline)copper(I) complex which acted to ‘catenate’ the nanoparticles into mechanically interlocked structures, which formed a stable yet chemically modifiable linking mechanism with well defined particle separation.

The mechanism behind this particle interlocking is simple and extremely effective (see figure). The copper(I) centre in the complex arranges two phenanthroline ligands in an orthogonal arrangement., while two phenyl substituents direct the polyethylene glycol (PEG) chains away from each side. The PEG chains, which bestow water solubility on the complex, are terminated with thiol groups which have a strong affinity for the nanoparticle surfaces. Once these thiol groups are attached to the nanoparticles, the system locks two particles together into a physically entwined aggregate. The group employed DLS, SERS and TEM in their analyses, three complementary experimental techniques which allowed them to develop a comprehensive picture of their interlocking nanoparticle systems.

The controlled assembly of nanoparticles into complex structures is extremely important in the quest to design and synthesise complex, efficient and multifunctional nanostructures. Strategies such as those employed in this work, which combines the exciting fields of supramolecular chemistry and nanoparticle design, will be extremely important in the future development of novel nanotechnologies.

To read this communication, click here.

Hot Article out now

Fabrication of biomimetic superhydrophobic surfaces inspired by lotus leaf and silver ragwort leaf

Jinyou Lin, Yu Cai, Xianfeng Wang, Bin Ding, Jianyong Yu and Moran Wang

Nanoscale, 2011, DOI: 10.1039/C0NR00812E, Paper

Inspired by the self-cleaning lotus leaf and silver ragwort leaf, the authors demonstrate the fabrication of biomimetic superhydrophobic fibrous mats via electrospinning polystyrene (PS) solution in the presence of silica nanoparticles. The  fibers they obtain present a fascinating structure with the combination of nano-protrusions and numerous grooves due to the rapid phase separation in electrospinning. The content of silica nanoparticles incorporated into the fibers proves to be the key factor affecting the fiber surface morphology and hydrophobicity. Read more…

Hot Article

A facile synthetic route for the preparation of gold nanostars with magnetic cores and their reusable nanohybrid catalytic properties

Xiumin Miao, Tingting Wang, Fang Chai, Xiuli Zhang, Chungang Wang and Wendong Sun

Nanoscale, 2011, Advance Article, DOI: 10.1039/C0NR00704H

Chungang Wang and colleagues develop a new synthetic route to prepare gold nanostars (GNSs) with Fe₃O₄ cores under mild conditions. The result is an easy way to obtain magnetic GNSs with tunable optical properties from the visible to near-infrared. Even more, the particles described also show catalytic activity and can be easily recycled using an external magnet.

Read the article now

New Nanoscale communication

New integrated elemental and molecular strategies as a diagnostic tool for the quality of water soluble quantum dots and their bioconjugates

Laura Trapiella-Alfonso, Antonio R. Montoro Bustos, Jorge Ruiz Encinar, Jose M. Costa-Fernandez, Rosario Pereiro and Alfredo Sanz-Medel

Nanoscale, DOI: 10.1039/c0nr00822b

Alfredo Sanz-Medel and co-workers at the University of Oviedo, Spain have developed a new strategy for analysing the quality of water soluble and bioconjugated quantum dots.

Their work is a novel concept based on size exclusion chromatography (SEC) coupled with elemental and fluorescence detection. Traditionally, it has been difficult to analyse the quality of quantum dot constructs in a quantitative fashion with methods such as transmission electron microscopy and photoluminescence spectroscopy. The current work aims to provide a general platform which allows a much greater understanding of the quality of quantum dots after water solubilisation and bioconjugation.

Although quantum dots exhibit many excellent properties for use in biomedical imaging, such as bright fluorescence and narrow emission lines, it is vital that these innately hydrophobic particles can be dispersed in water using a reliable capping procedure. Furthermore, for them to be used as functional probes in biological environments they need to be conjugated to other molecules, such as proteins or antibodies. As these steps are vital for development of quantum dot-based biomedical probes, there is an urgent need for advanced methods of purification and characterization of quantum dot bioconjugates, such as the one developed by this group.

Read more about this exciting work here.