A variety of advanced techniques have been developed to characterize the atherosclerotic plaque, including multidetector spiral computed tomography, magnetic resonance imaging, intravascular ultrasound, optical coherent tomography and intravascular near infrared spectroscopy.
Pu Wang and his colleagues from Purdue University, West Lafayette, and Indiana University School of Medicine (USA) now developed a promising new one: They employ an optical window between 1600 nm and 1850 nm for bond-selective deep tissue imaging. Label-free imaging of atherosclerotic plaques can be performed through optical excitation of first overtones of CH bonds and acoustic detection of the generated ultrasound waves in this previously underappreciated optical window.
Until now, the consensus was that the gold optical window lies between 650 and 1300 nm and that it stops at 1300 nm due to significant water absorption at longer wavelengths. The scientists noted that water absorption in the region beyond 1300 nm is modulated by the vibration transition of H2O: They observed a significant valley between 1600 and 1850 nm, where the absorption coefficient of pure water is at the same level as that of heme proteins in whole blood around 800 nm.
Considering the reduced scattering and diminished phototoxicity at longer wavelength excitation, the wavelength region from 1600 to 1850 nm is appealing as a new optical window for deep tissue imaging (light red shadow region). Importantly, the first overtone of CH vibration is located at the same window. Using this new window to carry out photoacoustic imaging, the scientists found a 5 times enhancement of photoacoustic signal by first overtone excitation of the methylene group CH2 at 1730 nm, compared to the second overtone excitation at 1210 nm.This enhancement allowed 3D mapping of intramuscular fat with improved contrast and of lipid deposition inside an atherosclerotic artery wall in the presence of blood. Moreover, lipid and protein could be differentiated based on the first overtone absorption profiles of CH2 and methyl group CH3 in this window.
Selective vibrational photoacoustic microscopy imaging of collagen and lipids heralds the potential in diagnosis of vulnerable plaques through detection of the thickness of the collagen cap and the location of the lipid-laden plaque inside the arterial wall without molecular labeling that could alter tissue composition. (Text contributed by K. Maedefessel-Herrmann)
J. Biophotonics, Volume 5, Issue 11 (2012)
Journal of Biophotonics publishes cutting edge research on interactions between light and biological material. The journal is highly interdisciplinary, covering research in the fields of physics, chemistry, biology and medicine. The scope extends from basic research to clinical applications. Connecting scientists who try to understand basic biological processes using light as a diagnostic and therapeutic tool, the journal offers a platform where the physicist communicates with the biologist and where the clinical practitioner learns about the latest tools for diagnosis of diseases. JBP offers fast publication times: down to 20 days from acceptance to publication. Latest Journal Impact Factor (2010): 4.240 (ISI Journal Citation Reports 2010)
Scientists enlist engineered protein to battle the MERS virus
22.05.2017 | University of Toronto
Insight into enzyme's 3-D structure could cut biofuel costs
19.05.2017 | DOE/Los Alamos National Laboratory
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.
Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...
22.05.2017 | Event News
17.05.2017 | Event News
16.05.2017 | Event News
22.05.2017 | Materials Sciences
22.05.2017 | Life Sciences
22.05.2017 | Physics and Astronomy