Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Versatile Capsules

15.04.2014

Multifunctional microcapsules made from metals and tannic acid

Microcapsules with a broad spectrum of applications in biomedicine, catalysis, and technology can be produced by using plant-derived, phenolic tannic acid and a variety of metals. The capsules are formed by a simple self-assembly process, and their properties can be controlled through the choice of metal, as demonstrated by a team of Australian and German researchers in the journal Angewandte Chemie.

Metals and organic molecules can combine to form coordination compounds whose structure and properties depend on the components. Examples from nature include the oxygen-binding heme groups in our red blood cells with their central iron atom or the magnesium complex at the heart of photosynthesis. Scientists have also explored the use of these types of compounds to build things, such as networked scaffold structures.

A team from the University of Melbourne, the Baker IDI Heart and Diabetes Institute (Melbourne, Australia), and the University Medical Center Freiburg (Germany), is particularly interested in structures in the form of hollow capsules. Led by Frank Caruso, these researchers haven now been able to demonstrate that a single organic ligand, tannic acid, can coordinate to 18 different metals to form capsules made of metal–phenolic networks (MPNs). The metals are aluminum, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, molybdenum, ruthenium, rhodium, cadmium, cerium, europium, gadolinium, and terbium.

... more about:
»ARC »MRI »PET »blood »copper »fluorescence »ions »rhodium »structures

The production method is simple: just mix tannic acid with a solution of the desired metal ion in the presence of a suitable substrate—in this case microparticles. Removal of the substrate leaves behind hollow microcapsules.

The properties of the capsules depend on the type and number of metal ions. For example, capsules with aluminum have a property profile suitable for drug transport: while they are relatively stable at pH values typical of blood, they come apart at the lower pH values found in some cell compartments. They could thus be used to transport a drug though the blood and release it after entering a cell.

Capsules with europium and terbium ions can be used for multicolored fluorescence labeling of biological samples, as well as for technological applications like flexible color displays. Capsules with manganese are highly promising contrast agents for magnetic resonance imaging (MRI). Capsules with radioactive copper isotopes are good tracers for positron emission tomography (PET). Properties like size, shape, and surface chemistry could be tailored to control the distribution of the capsules in the body. Capsules with radioactive copper and europium could allow for tissue samples to undergo PET followed immediately by fluorescence microscopy.

Catalysis is another possible application. The researchers were able to show that capsules with rhodium catalyze the hydrogenation of quinoline at least as well as conventional rhodium catalysts.

About the Author

Frank Caruso is a professor and Australian Research Council (ARC) Laureate Fellow at The University of Melbourne, Australia. He is also a Director of the ARC Centre of Excellence in Convergent Bio-NanoScience and Technology and is a Fellow of the Australian Academy of Science. His research interests focus on developing advanced nano- and biomaterials.

Author: Frank Caruso, University of Melbourne (Australia), http://www.chemeng.unimelb.edu.au/people/staff.php?person_ID=16579

Title: Engineering Multifunctional Capsules through the Assembly of Metal–Phenolic Networks

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201311136

Frank Caruso | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

Further reports about: ARC MRI PET blood copper fluorescence ions rhodium structures

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>