Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > The need for speed

Abstract:
Coherent Raman scattering methods have one key advantage over spontaneous Raman microscopy: speed. The (sub-)microsecond pixel dwell times offered by narrowband CRS imaging methods have initiated a new era of chemical imaging applications in biology and biomedicine.

The need for speed

Irvine, CA | Posted on May 25th, 2012

Biomedical scientists are dreaming of a technique showing the distribution of all the biomolecular constituents that make up biological tissue in high-resolution, three-dimensional maps. Such a visualization tool does not currently exist. Whereas fluorescence and refraction based techniques will never be able to identify an arbitrary molecular compound in tissue, vibrational imaging techniques offer much more promise. They work label-free and non-invasively and they are able to identify many important groups.

The conventional vibrational imaging technique is Raman microscopy. Practical limitations have so far prevented Raman microscopy from reaching its full potential. The most important limitation is speed. The intrinsically weak Raman signals severely limit the achievable image acquisition rate. The development of coherent Raman scattering (CRS) microscopy techniques over the last decade has resulted in important steps toward resolving the speed issue. In a feature article, Eric O. Potma and a team of scientists at the University of California (Irvine, USA) discuss several ways in which the improved speed of CRS microscopy has transformed the biomedical imaging field and touch on some of the challenges that lie ahead in moving towards the realization of a more generally applicable visualization technique.

Stronger signals are obtained because in CRS the molecules are driven coherently, which makes them radiate in unison. The resulting signal is coherently amplified through constructive interference in a well-defined, phase-matched direction which enables efficient detection of the Raman response. For instance, when the microscopic focal volume is filled with lipids, the number of detected photons in coherent anti-Stokes Raman scattering (CARS), generated from the CH2 stretching mode, can easily exceed 102 per microsecond at 10 mW of illumination. With such high signal levels, real-time Raman imaging of biological tissues becomes feasible.

An important application of high speed CRS imaging is the visualization of large tissue segments. For example, neural injuries and myelination disorders in live spinal tissues have been mapped as well as atherosclerotic plaques in aortas. Tissue maps were generated that cover up to several centimeters in lateral and hundreds of microns in axial distance, while preserving the (sub-)micrometer resolution offered by the high numerical aperture objective.

The intrinsic movement of the tissue, due to pulsation of blood vessels, breathing, or positional adjustments by the subject, poses a challenge when imaging living tissues. Imaging at video-rate enables image acquisition in which the individual frames show minimal blurring due to movements. Another advantage of fast imaging is the reduction of possible photodamage in living tissues. Besides live tissue imaging in small animal models, CRS imaging has already been applied to the examination of human skin in vivo.

In addition, the fast imaging modalities enable a time- and space-resolved view of dynamic processes of biological relevance. Water diffusion in neutrophile cells, the dynamics of intracellular droplets, and the diffusion of pharmaceutically relevant agents through skin are examples of dynamic processes that have been visualized.

Single frequency CARS and SRS have already proven indispensable in the study of lipids and lipid metabolism in live tissues and cells. Because of its imaging speed and chemical contrast, CRS has pushed the concept of label-free and noninvasive chemical imaging closer to clinical biomedical applications. The challenge ahead is to marry the speed qualities of single frequency scanning with the superior spectral information of broadband Raman spectroscopy. Recent developments suggest several approaches by which this could occur and provide a glimpse toward the ideal of clinically relevant, real-time chemical inspection of live tissues.

(Text contributed by K. Maedefessel-Herrmann)

J.L. Suhalim et al.; J. Biophotonics 5, 387-395 (2012); DOI 10.1002/jbio. 201200002

####

For more information, please click here

Contacts:
Regina Hagen
Journal Publishing Manager | Editorial Physics Department
Wiley-VCH Verlag GmbH & Co. KGaA
Rotherstr. 21, 10245 Berlin, Germany
Fon: +49 (0) 30/ 47 03 13 21
Fax: +49 (0) 30/ 47 03 13 99
E-Mail:

Copyright © Wiley-VCH Verlag GmbH & Co. KGaA

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

ICN2 researchers compute unprecedented values for spin lifetime anisotropy in graphene November 17th, 2017

Math gets real in strong, lightweight structures: Rice University researchers use 3-D printers to turn century-old theory into complex schwarzites November 16th, 2017

The stacked color sensor: True colors meet minimization November 16th, 2017

Nanometrics to Participate in the 6th Annual NYC Investor Summit 2017 November 16th, 2017

Nanometrics Announces $50 Million Share Repurchase Program November 15th, 2017

Imaging

The stacked color sensor: True colors meet minimization November 16th, 2017

Discoveries

ICN2 researchers compute unprecedented values for spin lifetime anisotropy in graphene November 17th, 2017

Math gets real in strong, lightweight structures: Rice University researchers use 3-D printers to turn century-old theory into complex schwarzites November 16th, 2017

The stacked color sensor: True colors meet minimization November 16th, 2017

Counterfeits and product piracy can be prevented by security features, such as printed 3-D microstructures: Forgeries and product piracy are detrimental to society and industry -- 3-D microstructures can increase security -- KIT researchers develop innovative fluorescent 3-D stru November 15th, 2017

Announcements

ICN2 researchers compute unprecedented values for spin lifetime anisotropy in graphene November 17th, 2017

Math gets real in strong, lightweight structures: Rice University researchers use 3-D printers to turn century-old theory into complex schwarzites November 16th, 2017

The stacked color sensor: True colors meet minimization November 16th, 2017

Nanometrics to Participate in the 6th Annual NYC Investor Summit 2017 November 16th, 2017

Tools

Nanometrics to Participate in the 6th Annual NYC Investor Summit 2017 November 16th, 2017

Nanometrics Announces $50 Million Share Repurchase Program November 15th, 2017

Nanometrics Board of Directors Names Pierre-Yves Lesaicherre President and CEO November 14th, 2017

Oxford Instruments announces winner of the 2017 Sir Martin Wood Prize for Japan November 14th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project