Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Illinois researchers combine weak chemical forces to strengthen a novel imaging technology

22.05.2014

When Associate Professor of Chemical and Biomolecular Engineering Hyunjoon Kong, graduate student Cartney Smith, and colleagues set out to improve MR imaging (MRI), they turned current contrast agent technology on its head—or rather, they turned it inside out.

 The new compound they designed in collaboration with Roger Adams Professor of Chemistry Steven C. Zimmerman is not only more effective, but also self-assembling. Kong is a member of the Regenerative Biology and Tissue Engineering research theme at the Institute for Genomic Biology.


Image created by Janet Sinn-Hanlon, DesignGroup@VetMed, University of Illinois

When doctors perform an MRI, they administer a contrast agent: a chemical that, when injected into the bloodstream or ingested by the patient just before the MRI, improves the clarity of structures or organs in the resulting image.  One common class of contrast agent, often used for imaging of blood vessels and internal bleeding, contains gadolinium, a rare-earth metal.

Recently, biomedical researchers have found ways to increase the effectiveness of certain contrast agents by associating them with nanoparticles.  The contrast agent being used is packaged inside or bonded to the surface of microscopic particles, which can be designed to target certain regions of the body or prolong the agent’s activity.

Researchers are now exploring the multipurpose use of nanoparticles.  If particles could be loaded with several types of contrast agents or dyes instead of one, or a contrast agent along with another type of diagnostic aid or a medication, doctors could more efficiently test for and treat conditions, and limit the number of injections received by patients.

Just like toddlers sharing a new toy, though, compounds packaged together into a nanoparticle cannot always play well together.  For example, contrast agents may bind to other chemicals, reducing their effectiveness.  In addition, when contrast agents are enclosed inside a nanoparticle, they may not work as well.  Attempts to attach agents to the outer surface of nanoparticles via covalent formation are also problematic, as they can negatively affect the activity of the nanoparticles or the compounds that they carry.

Kong, Smith and colleagues tackled these challenges by using interactions between naturally occurring biomolecules as a guide.  Many types of proteins are strongly attached to cell membranes not by covalent bonds, but by the sum of multiple weaker forces—the attraction of positive and negative charges, and the tendency of non-polar (oil-like) substances to seek each other and avoid water.

The group hypothesized that the same types of forces could be used to attach a contrast agent to the surface of a type of nanoparticle called a liposome, which resembles a little piece of cell membrane in the shape of a tiny bubble.  The researchers designed a “fastener” molecule, DTPA-chitosan-g-C18, that is charged, attracting it to the liposome and binding it to the contrast agent gadolinium. A nonpolar region anchors it to the liposome membrane.

In a series of experiments reported in a recent ACS Nano article (DOI: 10.1021/nn4026228), Kong and others demonstrated that their fastener molecule readily inserted itself into the membrane of pre-made liposomes.  Gadolinium stably associated with the modified nanoparticles in solution, and experiments in animal models showed that these nanoparticles produced clear diagnostic images.

“The strategy works like Velcro on a molecular level to adhere functional units to the outer leaflet of a liposome,” said Smith, who was first author on the study.  “This work represents a new material design strategy that is scalable and easily implemented.  The development of improved contrast agents has the potential to directly impact patients' lives by detecting damaged blood vessels.”

One of the difficulties of working with liposomes is their tendency to degrade inside the body.  When the fastener-loaded liposomes degraded, some of the efficacy of the gadolinium was lost.  In a second study published in Langmuir (DOI: 10.1021/la500412r), Kong and Smith developed a process for chemically cross-linking the components of the nanoparticle that prolonged the life of the nanoparticles in biological conditions.

The work reported in ACS Nano was a collaboration among Kong, Smith, Zimmerman, and others at the University of Illinois, as well as Dr. Sanjay Misra and researchers at the Mayo Clinic.  Both studies were supported by funding from the National Institutes of Health, as well as the University of Illinois Center for Advanced Study.

Written By: 
Claudia Lutz. Photos by L. Brian Stauffer and Janet Sinn-Hanlon.

Nicholas Vasi | Eurek Alert!

Further reports about: Biology MRI activity compounds liposomes nanoparticle nanoparticles particles

More articles from Life Sciences:

nachricht New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences

nachricht The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

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,...

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

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>