Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A New Coat for Golden Rods

12.12.2011
Gold isn’t just lovely in jewelry; it has long been used as medicine. Modern medicine is particularly focused on nanoscopic gold, which can be used as a contrast agent and in the treatment of cancer.

In the journal Angewandte Chemie, Eugene R. Zubarev and his team at Rice University in Houston (Texas, USA) have now introduced a new pretreatment process for gold nanorods that could accelerate their use in medical applications.

How can tiny rods of gold help to fight cancer? Cancer cells are more sensitive to temperature than healthy tissue, and this fact can be exploited through local heating of the affected parts of the body. This is where the gold nanorods come into play. They can be introduced into the cancer cells and the diseased areas irradiated with near-infrared light (photoinduced hyperthermia). The rods absorb this light very strongly and transform the light energy into heat, which they transfer to their surroundings.

Gold nanorods are normally produced in a concentrated solution of cetyl trimethylammonium bromide (CTAB) and are thus coated in a double layer of CTAB. The CTAB is only deposited onto the surface, not chemically bound. In an aqueous environment, the CTAB molecules slowly dissolve. This is problematic because CTAB is highly toxic. Simply leaving out the CTAB is no solution because without this coating the nanorods would clump together.

In order to make the rods stable as well as biocompatible, various more or less complex methods of pretreatment have been developed. However, for many of these processes, it is not known how much of the toxic CTAB remains on the nanorods. Another problem is that the pretreatment can disrupt the uptake of the nanorods into cells, which drastically reduces the success of photothermal cancer treatment.

Zubarev and his co-workers have now developed a new strategy that solves these problems: they replaced the CTAB with a variant that contains a sulfur-hydrogen group, abbreviated as MTAB. With various analytical processes, the scientists have been able to prove that the CTAB on these nanorods is completely replaced with an MTAB layer. The MTAB molecules chemically bond to gold nanorods through their sulfur atoms. They bind so tightly that the layer stays in place even in an aqueous solution and the rods can even be freeze-dried. They can be stored indefinitely as a brown powder and dissolve in water again within seconds.

Tests on cell cultures demonstrate that MTAB gold nanorods are not toxic, even at higher concentrations. In addition, they are absorbed in large amounts by tumor cells. The scientists estimate that under the conditions of their experiment, a single cell takes up more than two million nanorods. This would make effective photothermal tumor treatment possible.
About the Author
Dr Eugene Zubarev is an Associate Professor of Chemistry at Rice University, and has been working in the area of nanochemistry and nanomaterials for over 15 years. He is the recipient of the National Science Foundation Career Award and Alfred P. Sloan Research Fellowship.
Author: Eugene R. Zubarev, Rice University, Houston (USA), http://www.owlnet.rice.edu/~zubarev/group.htm
Title: Quantitative Replacement of Cetyl Trimethylammonium Bromide by Cationic Thiol Ligands on the Surface of Gold Nanorods and Their Extremely Large Uptake by Cancer Cells

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201107304

Eugene R. Zubarev | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht A Varied Menu
25.03.2019 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Key evidence associating hydrophobicity with effective acid catalysis
25.03.2019 | Tokyo Metropolitan University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Laser processing is a matter for the head – LZH at the Hannover Messe 2019

25.03.2019 | Trade Fair News

A Varied Menu

25.03.2019 | Life Sciences

‘Time Machine’ heralds new era

25.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>