Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New imaging technique able to watch molecular dynamics of neurodegenerative diseases

14.07.2017

Novel imaging approach could improve molecular-scale understanding of early disease stages

Researchers have developed a fast and practical molecular-scale imaging technique that could let scientists view never-before-seen dynamics of biological processes involved in neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis.


A new technique that provides both chemical composition and molecular orientation information at subsecond timescales could reveal new information about what occurs on the molecular level as diseases such as Alzheimer's and multiple sclerosis progress.

Credit: Sophie Brasselet, Institut Fresnel, CNRS, Aix Marseille Université

The new technique reveals a sample's chemical makeup as well as the orientation of molecules making up that sample, information that can be used to understand how molecules are behaving. What's more, it acquires this information in mere seconds, significantly faster than the minutes required by other techniques. The faster speed means it will be possible for the first time to watch disease progression in living animal models at the molecular level. With further development, the technique might also be used to detect early signs of neurodegenerative diseases in people.

In Optica, The Optical Society's journal for high impact research, researchers led by Sophie Brasselet of the Institut Fresnel, CNRS, Aix Marseille Université, France, report their new technique, called high-speed polarization resolved coherent Raman scattering imaging. They used artificial lipid membranes to demonstrate the technique's capabilities for enhancing neurological research.

The artificial membranes used in the study are made of packed layers of lipids that are similar to those found in the myelin sheath that covers axons to help electrical impulses move quickly and efficiently. When diseases such as Alzheimer's and multiple sclerosis progress, these lipids start to disorganize and the lipid layers lose their adhesion. This ultimately causes the myelin sheath to detach from the axon and leads to malfunctioning neural signals.

"We designed a technique able to image molecular organization in cells and tissues that can ultimately let us see the early stage of this detachment and how lipids are organized within this myelin sheath," said Brasselet. "This could help us understand the progression of diseases by identifying the stage at which lipids start disorganizing, for example, and what molecular changes are occurring during this time. This could allow new targeted drug treatments that work differently than those used now."

Watching molecules in real time

The new technique developed by Brasselet and her research team makes use of a nonlinear effect called coherent Raman scattering that occurs when light interacts with molecules. The frequency, or wavelength, of the nonlinear signal provides the chemical makeup of a sample based on its molecular vibrations, without the need to add any additional fluorescent labels or chemicals.

The researchers built on an existing approach called stimulated Raman scattering imaging, which enhances the Raman signal by modulating the laser light's intensity, or power. To obtain molecular orientation information from the coherent Raman signal, the researchers used an electro-optical device called a Pockels cell to quickly modulate the laser's polarization rather than its intensity.

"We took the concept of intensity modulation used for stimulated Raman scattering and transposed it to polarization modulation using an off-the-shelf device," said Brasselet. "The signal detection for our technique is very similar to what is done with stimulated Raman scattering, except that instead of detecting only the intensity of the light, we detect polarization information that tells us if molecules are highly oriented or totally disorganized."

The key, however, is to acquire orientation information fast enough to capture highly dynamic biological processes on a molecular level. Previous methods were slow because they acquired an image, then the polarization information, and then repeated the process to capture changes over time. By modulating the laser polarization very fast, the researchers could take measurements pixel by pixel, in real time.

With the new approach, it takes less than a second to acquire lipid orientation information in a large image that contains several cells. This information is then used to construct a sequence of "lipid order" images that shows molecular orientation dynamics at subsecond time scales.

Measuring single membranes

The researchers showed that their technique could reveal deformation and lipid organization in artificial lipid membranes resembling the packed membranes of myelin. The technique was even sensitive enough to measure the organization of lipids around red blood cells, which have only a single lipid membrane.

"Even though we only demonstrated the technique with model membranes and single cells, this technique is translatable to biological tissue," said Brasselet. "It will show us how molecules behave, information that is not available from the micron-scale morphological images taken with traditional microscopy techniques."

Brasselet said that the new technique could be used in the near future to better understand progression in diseases that involve a breakdown of the myelin sheath, such as Alzheimer's and multiple sclerosis. For example, it could be used to image neurons in living mice by combining the Raman scattering technique with existing methods in which tiny windows are implanted in the brains and spinal cords of laboratory animals.

"Ultimately, we would like to develop coherent Raman imaging so that it could be used in the body to detect diseases in their early stages," said Brasselet. "To do this, the technique would have to be adapted to work with endoscopes or other tools in development that allow light-based imaging inside the body."

###

Paper: M. Hofer, N.K. Balla, S. Brasselet, "High speed polarization resolved coherent Raman scattering imaging," Optica, Volume 4, Issue 7, 795-801 (2017).
DOI: 10.1364/OPTICA.4.000795

About Optica

Optica is an open-access, online-only journal dedicated to the rapid dissemination of high-impact peer-reviewed research across the entire spectrum of optics and photonics. Published monthly by The Optical Society (OSA), Optica provides a forum for pioneering research to be swiftly accessed by the international community, whether that research is theoretical or experimental, fundamental or applied. Optica maintains a distinguished editorial board of more than 40 associate editors from around the world and is overseen by Editor-in-Chief Alex Gaeta, Columbia University, USA. For more information, visit Optica.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.

Media Contacts:

Rebecca B. Andersen
The Optical Society randersen@osa.org
202-416-1435

Joshua Miller
The Optical Society
jmiller@osa.org
202-416-1435

Media Contact

Joshua Miller
jmiller@osa.org
202-416-1435

 @opticalsociety

http://www.osa.org 

Joshua Miller | EurekAlert!

More articles from Medical Engineering:

nachricht MRI technique differentiates benign breast lesions from malignancies
20.02.2018 | Radiological Society of North America

nachricht True to type: From human biopsy to complex gut physiology on a chip
14.02.2018 | Wyss Institute for Biologically Inspired Engineering at Harvard

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Decoding the structure of the huntingtin protein

22.02.2018 | Life Sciences

Camera technology in vehicles: Low-latency image data compression

22.02.2018 | Information Technology

Minimising risks of transplants

22.02.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>