Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Platinum Cages

Abstract:
Liposomes as blueprints for hollow platinum nanospheres

Platinum Cages

Posted on November 2, 2006

It looks like lather under an electron microscope: American researchers have successfully produced porous, nanoscopic, hollow platinum spheres by using liposomes as blueprints.

Tiny structures made of precious metals are of interest because of their broad spectrum of biomedical, catalytic, and optical applications. Porous nanospheres, for example, are ideal for catalytic applications that require large surfaces but can work at low concentration (and consequently with little material). Previous production methods had a disadvantage in that the spheres consisted of individual metallic nanoparticles; these were not very stable and only relatively small spheres were accessible. A team at the Sandia National Laboratories and the University of New Mexico in Albuquerque as well as the University of Georgia in Athens has now developed a clever new technique for the production of relatively large porous platinum nanocages. These spheres do not consist of individual particles, but of continuous, branched (dendritic) platinum sheets.

Liposomes are familiar to us from creams: the tiny balls of fat carry active ingredients through the skin. In the liposome that researchers working with John A. Shelnutt used as a blueprint, the mantle of fat consists of a double lipid layer. The narrow space between the two layers contains a light-activated catalyst, a tin-containing porphyrin compound. (Porphyrin frameworks are also an important component of hemoglobin.) The liposomes are placed in a solution containing a platinum salt. When these liposomes are then irradiated with light, the photocatalyst transfers electrons to the platinum ions. The resulting uncharged platinum atoms gather into tiny clumps. Once these clumps reach a certain size, they also become active and catalyze the release of more platinum atoms from the platinum salt. Atom by atom, small, flat, branched platinum structures (dendrites) form within the double lipid layer. These continue to grow until all of the platinum salt is consumed. The important thing is to make sure that the number of tin photocatalyst moleculesóand thus the initial number of platinum clumpsówithin the liposome double layer is very high. The resulting dendrites are then close enough to each other to grow into a network; this forms a solid but porous sphere with the same size and shape as the liposome. When the liposomes are broken up, the platinum spheres remain intact. Shelnutt, his collaborator Yujiang Song, and their team were able to produce spheres with diameters up to 200 nm. These platinum spheres aggregate into foam-like structures.

####


Author: John A. Shelnutt, University of Georgia, Athens (USA), jasheln.unm.edu/

Title: Synthesis of Platinum Nanocages by Using Liposomes Containing Photocatalyst Molecules

Angewandte Chemie International Edition, doi: 10.1002/anie.200602403

Contact:
Editorial office:
angewandte@wiley-vch.de

or David Greenberg (US)
dgreenbe@wiley.com

or Julia Lampam (UK)
jlampam@wiley.co.uk

Copyright © Angewandte Chemie

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Possible Futures

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

Harris & Harris Group Portfolio Company D-Wave Systems Announces 1,000 Qubit Processor and is Discussed in the Economist June 23rd, 2015

Global Nanoclays Market Analysis, Size, Growth, Trends And Segment Forecasts, 2015 To 2022: Grand View Research, Inc June 15th, 2015

Healthcare Nanotechnology (Nanomedicine) Market Size To 2020 June 5th, 2015

Materials/Metamaterials

Production of Zirconium Carbide Nanoparticles at Low Temperature without Thermal Operations July 5th, 2015

Pioneering Southampton scientist awarded prestigious physics medal July 3rd, 2015

New technology using silver may hold key to electronics advances July 2nd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

Announcements

Production of Zirconium Carbide Nanoparticles at Low Temperature without Thermal Operations July 5th, 2015

A 'movie' of ultrafast rotating molecules at a hundred billion per second: A quantum wave-like nature was successfully observed in rotating nitrogen molecules July 4th, 2015

New Biosensor Produced in Iran to Detect Effective Drugs in Cancer Treatment July 4th, 2015

Pioneering Southampton scientist awarded prestigious physics medal July 3rd, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project