Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanoparticle pinpoints blood vessel plaques

07.02.2014
A step toward indentifying plaques vulnearble to rupture and cause heart attack and stroke

A team of researchers, led by scientists at Case Western Reserve University, has developed a multifunctional nanoparticle that enables magnetic resonance imaging (MRI) to pinpoint blood vessel plaques caused by atherosclerosis.

The technology is a step toward creating a non-invasive method of identifying plaques vulnerable to rupture–the cause of heart attack and stroke—in time for treatment.

Currently, doctors can identify only blood vessels that are narrowing due to plaque accumulation. A doctor makes an incision and slips a catheter inside a blood vessel in the arm, groin or neck. The catheter emits a dye that enables X-rays to show the narrowing.

However, Case Western Reserve researchers report online today in the journal Nano Letters that a nanoparticle built from a rod-shaped virus commonly found on tobacco locates and illuminates plaque in arteries more effectively and with a tiny fraction of the dye.

More importantly, the work shows that the tailored nanoparticles home in on plaque biomarkers. That opens the possibility that particles can be programmed to identify vulnerable plaques from stable, something untargeted dyes alone cannot.

"From a chemist's point of view, it's still challenging to make nanoparticles that are not spherical, but non-spherical materials are advantageous for medical applications" said Nicole F. Steinmetz, assistant professor of biomedical engineering at Case Western Reserve. "Nature is way ahead of us. We're harvesting nature's methods to turn them into something useful in medicine."

The rod-shaped nanoparticles are made from tobacco mosaic virus, tiny tubular organisms that infect plant cells but are benign outside the plant.

Steinmetz, a specialist in bioengineering plant viruses, teamed with Xin Yu, a professor of biomedical engineering, who specializes in developing MRI techniques to investigate cardiovascular diseases. They created a device that transports and concentrates imaging agents on plaques.

The research team includes: Michael A. Bruckman, a postdoctoral researcher, and Lauren N. Randolph, an undergraduate student, in the Steinmetz lab; Kai Jiang, a PhD student in Yu's lab; and Leonard G. Luyt, assistant professor, and Emily J. Simpson, a PhD candidate, both at department of chemistry at Western University, in London, Ontario.

Elongated nanoparticles have a higher probability of being pushed out of the central blood flow and targeting the vessel wall compared to spheres. Further the shape allows more stable attachment to the plaque, the researchers said.

The virus surface is modified to carry short chains of amino acids, called peptides, that make the virus stick where plaques are developing or already exist. Luyt and Simpson synthesized the peptides.

"The binding allows the particle to stay on the site longer, whereas the sheer force is more likely to wash away a sphere, due to its high curvature," said Yu, an appointee of the Case School of Engineering.

The virus surface was also modified to carry near-infrared dyes used for optical scanning, and gadolinium ions (which are linked with organic molecules, to reduce toxicity of the metal) used as an MRI contrasting agent. They used optical scans to verify the MRI results.

By loading the surface with gadolinium ions instead of injecting them and letting them flow freely in the blood stream, the nanoparticle increases the relaxivity—or contrast from healthy tissue—by more than four orders of magnitude.

"The agent injected in the blood stream has a relaxivity of 5, and our nanoparticles a relaxivity of 35,000," said Steinmetz who was appointed by the Case Western Reserve School of Medicine.

That's because the nanorod carries up to 2,000 molecules of the contrast agent, concentrating them at the plaque sites. Secondly, attaching the contrast agent to a nanoparticle scaffold reduces its molecular tumbling rates and leads to additional relaxivity benefit, the researchers explained.

While the view is better, they are able to use 400 times less of the contrast agent because it's delivered directly to plaques.

The tobacco virus-based nanoparticle, they said, offers another advantage: Most nanoparticles that have been developed to carry contrast agents are based on synthetic materials, some of which may stay in the body a while.

The tobacco virus is made of protein, which the body is well equipped to handle and flush from the system rapidly.

Steinmetz and Yu, members of the Case Center for Imaging Research, are now proposing to take the work a step further. They want to tailor the nanoparticles to show doctors whether the plaques are stable and require no treatment, or are vulnerable to rupture and require treatment. A rupture sets off the cascade of events that lead to heart attack and stroke.

To do this, they must first find different biomarkers of stable versus vulnerable plaques and coat the nanoparticles with different peptides and contrast agents that enable the MRI to tell one from the other.

"Our understanding of vulnerable plaques is incomplete, but once we can diagnose vulnerable plaques from stable plaques, it will be a paradigm shift in diagnosis and prognosis," Yu said.

In addition to using the technology to find vulnerabilities, it may also useful for delivering medicines and monitoring treatment, the researchers say.

Kevin Mayhood | EurekAlert!
Further information:
http://www.case.edu

More articles from Life Sciences:

nachricht An evolutionary heads-up – The brain size advantage
22.05.2015 | Veterinärmedizinische Universität Wien

nachricht Endocrine disrupting chemicals in baby teethers
21.05.2015 | Goethe-Universität Frankfurt am Main

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...

Im Focus: IoT-based Advanced Automobile Parking Navigation System

Development and implementation of an advanced automobile parking navigation platform for parking services

To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...

Im Focus: First electrical car ferry in the world in operation in Norway now

  • Siemens delivers electric propulsion system and charging stations with lithium-ion batteries charged from hydro power
  • Ferry only uses 150 kilowatt hours (kWh) per route and reduces cost of fuel by 60 percent
  • Milestone on the road to operating emission-free ferries

The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...

Im Focus: Into the ice – RV Polarstern opens the arctic season by setting course for Spitsbergen

On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.

RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...

Im Focus: Gel filled with nanosponges cleans up MRSA infections

Nanoengineers at the University of California, San Diego developed a gel filled with toxin-absorbing nanosponges that could lead to an effective treatment for skin and wound infections caused by MRSA (methicillin-resistant Staphylococcus aureus), an antibiotic-resistant bacteria. This "nanosponge-hydrogel" minimized the growth of skin lesions on mice infected with MRSA - without the use of antibiotics. The researchers recently published their findings online in Advanced Materials.

To make the nanosponge-hydrogel, the team mixed nanosponges, which are nanoparticles that absorb dangerous toxins produced by MRSA, E. coli and other...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International symposium: trends in spatial analysis and modelling for a more sustainable land use

20.05.2015 | Event News

15th conference of the International Association of Colloid and Interface Scientists

18.05.2015 | Event News

EHFG 2015: Securing health in Europe. Balancing priorities, sharing responsibilities

12.05.2015 | Event News

 
Latest News

Mesoporous Particles for the Development of Drug Delivery System Safe to Human Bodies

22.05.2015 | Materials Sciences

Computing at the Speed of Light

22.05.2015 | Information Technology

Development of Gold Nanoparticles That Control Osteogenic Differentiation of Stem Cells

22.05.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>