The new method could be used to take precise three-dimensional images of plaques lining arteries, said Ji-Xin Cheng, an associate professor of biomedical engineering and chemistry at Purdue University.
"You would have to cut a cross section of an artery to really see the three-dimensional structure of the plaque," Cheng said. "Obviously, that can't be used for living patients."
The imaging reveals the presence of carbon-hydrogen bonds making up lipid molecules in arterial plaques that cause heart disease. The method also might be used to detect fat molecules in muscles to diagnose diabetes and for other lipid-related disorders, including neurological conditions and brain trauma. The technique also reveals nitrogen-hydrogen bonds making up proteins, meaning the imaging tool also might be useful for diagnosing other diseases and to study collagen's role in scar formation.
"Being able to key on specific chemical bonds is expected to open a completely new direction for the field," Cheng said
Findings are detailed in a paper to be published in Physical Review Letters and expected to appear in the June 17 issue. The findings represent the culmination of four years of research led by Cheng and doctoral student Han-Wei Wang.
The new technique uses nanosecond laser pulses in the near-infrared range of the spectrum. The laser generates molecular "overtone" vibrations, or wavelengths that are not absorbed by the blood. The pulsed laser causes tissue to heat and expand locally, generating pressure waves at the ultrasound frequency that can be picked up with a device called a transducer.
"We are working to miniaturize the system so that we can build an endoscope to put into blood vessels using a catheter," Cheng said. "This would enable us to see the exact nature of plaque formation in the walls of arteries to better quantify and diagnose cardiovascular disease."
Lihong Wang, Gene K. Beare Distinguished Professor of Biomedical Engineering at Washington University in St. Louis, is a pioneer of using the "photoacoustic" imaging of blood vessels based on the absorption of light by the electrons in hemoglobin.
The Purdue researchers are the first to show that a strong photoacoustic signal can arise from the absorption of light by the chemical bonds in molecules. The near-infrared laser causes enough heating to generate ultrasound but not enough to damage tissue.
"You can measure the time delay between the laser and the ultrasound waves, and this gives you a precise distance, which enables you to image layers of the tissues for three-dimensional pictures," Cheng said. "You do one scan and get all the cross sections. Our initial target is cardiovascular disease, but there are other potential applications, including diabetes and neurological conditions."
The approach represents a major improvement over another imaging technique, called coherent anti-Stokes Raman scattering, or CARS, which has been used by the Purdue-based lab to study three-dimensional plaque formation in arteries.
Also leading the research are Michael Sturek, chair of the Department of Cellular and Integrative Physiology at the Indiana University School of Medicine; Robert P. Lucht, Purdue's Ralph and Bettye Bailey Professor of Combustion in Mechanical Engineering; and David Umulis, a Purdue assistant professor of agricultural and biological engineering. Other authors of the paper include Purdue graduate students Ning Chai, Pu Wang and Wei Dou and Washington University postdoctoral researcher Song Hu.
Findings are based on research with pig tissues in laboratory samples and also with live fruit flies.
"You can see fat inside fly larvae, representing the potential to study how obesity affects physiology in humans," Cheng said.
Research funding came from the National Institutes of Health and American Heart Association.
Writer: Emil Venere, 765-494-4709, email@example.com
Source: Ji-Xin Cheng, 765-494-4335, firstname.lastname@example.org
Note to Journalists: Ji-Xin Cheng is pronounced "Gee-Shin." An electronic copy of the paper is available from Emil Venere, Purdue News Service, at 765-494-4709, email@example.com
Emil Venere | EurekAlert!
A Challenging European Research Project to Develop New Tiny Microscopes
28.03.2017 | Technische Universität Braunschweig
3-D visualization of the pancreas -- new tool in diabetes research
15.03.2017 | Umea University
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences