Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Penn molecular scientists develop color-changing stress sensor

19.08.2011
It is helpful — even life-saving — to have a warning sign before a structural system fails, but, when the system is only a few nanometers in size, having a sign that's easy to read is a challenge.

Now, thanks to a clever bit of molecular design by University of Pennsylvania and Duke University bioengineers and chemists, such warning can come in the form of a simple color change.


This is an enhanced image of a polymersome changing color under stress. Credit: Neha Kamat, University of Pennsylvania

The study was conducted by professor Daniel Hammer and graduate students Neha Kamat and Laurel Moses of the Department of Bioengineering in Penn's School of Engineering and Applied Science. They collaborated with associate professor Ivan Dmochowski and graduate student Zhengzheng Liao of the Department of Chemistry in Penn's School of Arts and Sciences, as well as professor Michael Therien and graduate student Jeff Rawson of Duke.

Their work was published in the journal Proceedings of the National Academy of Sciences.

The researchers' work involves two molecules: porphyrins, a class of naturally occurring pigments, and polymersomes, artificially engineered capsules that can carry a molecular payload in their hollow interiors. In this case, Kamat and Liao hypothesized that polymersomes could be used as stress sensors if their membranes were embedded with a certain type of light-emitting porphyrins.

The Penn researchers collaborated with the Therien lab, where the porphyrins were originally developed, to design polymersomes that were studded with the light-emitting molecules. When light is shined on these labeled polymersomes, the porphyrins absorb the light and then release it at a specific wavelength, or color. The Therien lab's porphyrins play a critical role in using the polymersomes as stress sensors, because their configuration and concentration controls the release of light.

"When you package these porphyrins in a confined environment, such as a polymersome membrane, you can modulate the light emission from the molecules," Hammer said. "If you put a stress on the confined environment, you change the porphyrin's configuration, and, because their optical release is tied to their configuration, you can use the optical release as a direct measure of the stress in the environment."

For example, the labeled polymersomes could be injected into the blood stream and serve as a proxy for neighboring red blood cells. As both the cells and polymersomes travel through an arterial blockage, for example, scientists would be able to better understand what happens to the blood cell membranes by making inferences from the stress label measurements.

The researchers calibrated the polymersomes by subjecting them to several kinds of controlled stresses — tension and heat, among others — and measuring their color changes. The changes are gradations of the near infrared spectrum, so measurements must be made by computers, rather than the naked eye. Rapidly advancing body-scanning technology, which uses light rather than magnetism or radiation, is well suited to this approach.

Other advances in medicine could benefit, as well. As cutting-edge pharmaceutical approaches already use similar molecular technology, the researchers' porphyrin labeling system could be integrated into medicine-carrying polymersomes.

"These kinds of tools could be used to monitor drug delivery, for example," Kamat said. "If we have a way to see how stressed the container is over time, we know how much of the drug has come out."

And, though the researchers chose the engineered polymersomes due to the wide range of stress they can endure, the same stress-labeling technique could soon be applied directly to naturally occurring tissues.

"One future application for this is to use dyes like these porphyrins but include them directly in a cellular membranes," Kamat said. "No one has taken a look at the intrinsic stress inside a membrane so these molecules would be perfect for the job."

The work was supported by the National Institutes of Health, the National Science Foundation and its Materials Research Science and Engineering Center program and the National Center for Research Resources.

Kamat is an NSF Graduate Fellow.

Evan Lerner | EurekAlert!
Further information:
http://www.upenn.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

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

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | 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

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>