Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Golden Rods

08.09.2008
For medical applications: production of gold nanorods without the use of cytotoxic additives

Gold nanoparticles are under consideration for a number of biomedical applications, such as tumor treatment. A German-American research team at Carnegie Mellon University in Pittsburgh, Hunter College in New York, and the RWTH Aachen has now developed a new method for the production of nanoscopic gold rods.

In contrast to previous methods, they have achieved this without the use of cytotoxic additives. As they report in the journal Angewandte Chemie, the synthesis is not carried out in water, but in an ionic liquid, a “liquid salt”.

Cancer cells are relatively temperature-sensitive. This is exploited in treatments involving overheating of parts of the cancer patient’s body. One highly promising method is photoinduced hyperthermia, in which light energy is converted to heat. Gold nanoparticles absorb light very strongly in the near infrared, a spectral region that is barely absorbed by tissue. The absorbed light energy causes the gold particles to vibrate and is dissipated into the surrounding area as heat. The tiny gold particles can be functionalized so that the specifically bind to tumor cells. Thus, only cells that contain gold particles are killed off.

The problem? Ordinary spherical gold particles do not efficiently convert the light energy into heat; only rod-shaped particles will do. Unfortunately, the additives needed to crystallize the rod-shaped particles from aqueous solutions are cytotoxic.

The team headed by Michael R. Bockstaller is now pursuing a new strategy: instead of aqueous solution, they chose to use an ionic liquid as their medium of crystallization. Ionic liquids are “liquid salts”, organic compounds that exist as oppositely charged ions, but in the liquid state. In this way, the researchers have been able to produce gold nanorods without the use of any cytotoxic additives.

In the first step, seed crystals are produced in the form of tiny spherical gold particles. These crystals are added to a “secondary growth solution” containing monovalent gold ions, silver ions, and the weak reducing agent ascorbic acid. The solvent is an imidazolium-based ionic liquid. In this medium, the crystals don’t continue to grow into spheres; instead they form rods with the round crystallization nuclei as “heads”. The mechanism is presumed to involve the various, energetically inequivalent surfaces of the crystal lattice: the aromatic, nitrogen-containing five-membered rings of the ionic liquid prefer to accumulate at the highly energetic facets of gold surfaces. They thus stabilize crystal shapes that have fewer low-energy facets than the normal spherical equilibrium form. This results in long rods.

Author: Michael R. Bockstaller, Carnegie Mellon University, Pittsburgh (USA), http://neon.mems.cmu.edu/people/bockstaller.htm

Title: Imidazolium-Based Ionic Liquids as Efficient Shape-Regulating Solvents for the Synthesis of Gold Nanorods

Angewandte Chemie International Edition 2008, 47, No. 40, doi: 10.1002/anie.200802185

Michael R. Bockstaller | Angewandte Chemie
Further information:
http://pressroom.angewandte.org
http://neon.mems.cmu.edu/people/bockstaller.htm

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>