Scanning Technique Can Be Used To See Stiffness Of Material Using Light

A new report published in Nature Photonics highlights the work from a global community of experts about how to determine a material’s stiffness, just by using light.

Brillouin light scattering spectroscopy (often just called Brillouin spectroscopy or BLS) is a technique experts use to study very tiny vibrations in materials, using light instead of sound.

When a laser light hits these vibrations, called phonons, some of the light changes colour slightly. The amount of shift in colour tells you about the speed of sound, an elastic property of the material —so this technique helps researchers understand how stiff and elastic a substance is and with a resolution comparable to optical microscopy. This is an unprecedented capability in materials characterisation.

This process is being used in physics, materials science, and biology and allows scientists to study materials at the microscopic level without damaging them. This is particularly useful for understanding the mechanical properties of soft tissues down to the cellular scale. For instance, it can reveal the differences in stiffness between normal and cancer cells. With the technique being so new and adopted in different parts of the world, it's important to standardise best practices and agree on basic principles.

This novel technology has great potential in the life sciences, where the elastic properties of biological tissues remain largely unknown. For instance, it has been recently reported that the elasticity of metastatic cells and their ability to invade tissues is associated with lower elasticity. Fernando Perez-Cota, Assistant Professor, University of Nottingham’s Faculty of Engineering

He added: "Understanding these relationships has tremendous implications for our understanding of cancer and other diseases. Reaching a consensus in the global community in this field is a great step forward towards standardisation and future translation to real world applications."

At Nottingham, researchers at the Optics and Photonics group are currently using their take of this technology to study several aspects of biology including the elastic properties of cancer cells and tissues, plant roots and sperm cells.

Sal La Cavera iii, a Royal Academy of Engineering Research Fellow and Nottingham Research Fellow in the Faculty of Engineering's Optics and Photonics Research Group, said of the research: "Stiffness is an important property of living things right down to the cellular level, for example the stiffness in cancer. This new technique is the first to offer a non-invasive way to study this material property in biology.

"With the technique being so new, it is important to gather the community and determine what best practice is and agree on common principles. This will unite the field in a way that allows the technology to progress more rapidly towards real-world clinical applications."

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