Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Small Golden Cosmos

29.08.2014

Planet–satellite nanostructures from gold nanoparticles and RAFT star polymers

The cosmos in miniature: German researchers have produced nanoparticles surrounded by a group of smaller nanoparticles like a planet orbited by satellites.


They equipped larger gold nanoparticles with special star-shaped polymers, which in turn bind to smaller gold nanoparticles. As the researchers report in the journal Angewandte Chemie, it is possible to precisely control the distance between the tiny “satellites” and their central “planet” by means of the molecular weight—and thus the chain length—of the polymers.

Like all humans, researchers like good aesthetics. They take pleasure in unusual nanoscopic architectures with ordered structures and are curious about what interesting physical properties are inherent to such structures. These properties can often be extremely useful.

For example, nanoarchitectures consisting of a central nanoparticle surrounded by smaller nanoparticles at a precisely defined distance could be used as sensors, as “rulers” for measuring biological nano-objects, and as transport systems to deliver drugs specifically to tumor cells. However, researchers had not previously found a method to easily and efficiently produce a variety of planet–satellite nanosystems—a critical requirement for the investigation and practical use of such nanoarchitectures.

Christin Rossner and Philipp Vana at the University of Göttingen have now developed such a technique. At its center are polymers produced by a RAFT (reversible addition–fragmentation chain transfer) polymerization. RAFT is a technique for the targeted synthesis of polymers with a precisely defined degree of polymerization; it results in very uniform polymers with precisely controllable chain lengths.

Because this is a controlled process, it is also possible to synthesize more complicated molecular architectures, such as comb-shaped or star-shaped polymers. Rossner and Vana chose to use star polymers consisting of a center with four side chains coming out like rays. The side chains have trithiocarbonate groups at their ends. These groups bind very well to gold surfaces.

The researchers treated gold nanoparticles with these star polymers. Two to three of the “rays” bind to the surface while the remaining one or two rays remain free and available to bind the smaller satellite gold nanoparticles later. The molecular weight of the star polymers—and thus the length of the rays—can be used to precisely control the distances between the planets and satellites. The satellites can also be equipped with polymer chains that have certain chemical groups on their ends. It is thus possible to make gold nanoparticle scaffolds with a variety of reactive groups at a defined distance form the central core.

About the Author

Dr. Philipp Vana is Professor of Macromolecular Chemistry at the University of Göttingen. His research focuses on tailoring macromolecules and nanocomposites using controlled polymerizations and on the design of new functional polymers. He is also Director of the Institute of Physical Chemistry in Göttingen and has been awarded several prizes and fellowships including the prestigious Heisenberg Professorship of the DFG.

Author: Philipp Vana, Universität Göttingen (Germany), http://www.mmc.chemie.uni-goettingen.de/

Title: Planet–Satellite Nanostructures Made To Order by RAFT Star Polymers

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201406854

Philipp Vana | Angewandte Chemie

Further reports about: Cosmos RAFT nanoparticle nanoparticles polymerization properties satellites structures technique

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>