A Small Golden Cosmos

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

Media Contact

Philipp Vana Angewandte Chemie

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors