Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Skewered Pumpkins

10.03.2008
Switchable nanovalves: pH-sensitive pseudorotaxane as reversible gate for drug nanotransporter

We encounter valves every day, whether in the water faucet, the carburetor in our car, or our bicycle tire tube. Valves are also present in the world of nanotechnology. A team of researchers headed by J. Fraser Stoddart and Jeffrey I. Zink at the University of California, Los Angeles, has now developed a new nanovalve.

In the journal Angewandte Chemie, the scientists reveal what is special about it: In contrast to prior versions, which only function in organic solvents, this valve operates in an aqueous environment and under physiological conditions—prerequisites for any application as a gate for nanoscopic drug-transport agents, which need to set their cargo free at the right place and time.

In order for pharmaceuticals to affect only the target diseased organ, suitable nanopackaging is required to bring the drug to the target area and release it only there. One example of a good nanoscopic packaging agent is a tiny sphere of porous silica. Its pores can be filled with the drug and closed with tiny controllable valves.

... more about:
»Value »Valve »pores

The scientists attached stem-shaped molecules onto the surface of the porous spheres and filled the pores with guest molecules. At neutral to acidic pH values, they stacked cucurbituril molecules onto these “stems”. Cucurbituril is a fat, ring-shaped molecule reminiscent of a pumpkin that has both ends hollowed out. The resulting supramolecular structure, which resembles a skewered pumpkin and is known to chemists as a pseudorotaxane, blocks the pores, so that the guest molecules cannot exit. The nanovalve is closed.

If the pH value is raised into the basic range, however, the interaction between the “pumpkins” and the “skewers” is weakened, and the pumpkins come off, opening the pores. Now the valves are open and the guest molecules can exit.

At this point the molecular details of the individual components still need to be tweaked. The goal: very small differences in pH values between healthy and diseased tissue should be sufficient to switch the valves and release the drug only in diseased cells.

Author: Jeffrey I. Zink, University of California, Los Angeles (USA), http://www.chem.ucla.edu/dept/Faculty/jzink/

Title: pH-Responsive Supramolecular Nanovalves Based on Cucurbit[6]uril Pseudorotaxanes

Angewandte Chemie International Edition 2008, 47, No. 12, 2222–2226, doi: 10.1002/anie.200705211

Jeffrey I. Zink | Angewandte Chemie
Further information:
http://www.chem.ucla.edu/dept/Faculty/jzink/
http://pressroom.angewandte.org

Further reports about: Value Valve pores

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Water world

20.11.2017 | Life Sciences

Less is more to produce top-notch 2D materials

20.11.2017 | Materials Sciences

Carefully crafted light pulses control neuron activity

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>