Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Opening a new window

09.12.2011
Water is opaque for wavelengths longer than 1300 nm limiting the optical spectroscopy of biological specimen. Yet, a local minimum of water absorption between 1600 nm and 1850 nm opens up a window for bond-selective deep tissue imaging such as mapping of atherosclerotic plaques.

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)

P. Wang et al., J. Biophotonics 5(1), 25-32 (2012), http://dx.doi.org/10.1002/jbio.201100102

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)

Regina Hagen | Wiley-VCH Verlag GmbH & Co. KGaA
Further information:
http://www.biophotonics-journal.com
http://dx.doi.org/10.1002/jbio.201100102

More articles from Life Sciences:

nachricht CWRU researchers find a chemical solution to shrink digital data storage
22.06.2017 | Case Western Reserve University

nachricht Warming temperatures threaten sea turtles
22.06.2017 | Swansea University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

New technique makes brain scans better

22.06.2017 | Medical Engineering

CWRU researchers find a chemical solution to shrink digital data storage

22.06.2017 | Life Sciences

Warming temperatures threaten sea turtles

22.06.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>