Breakthrough technique reveals genetic expression in fish by 'listening to light'

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London, July 1 (ANI): A collaborative team of scientists from the Helmholtz Zentrum Munchen and the Technische Universitat Munchen are using a combination of light and ultrasound to visualize fluorescent proteins that are seated several centimetres deep into living tissue.

Their work attains significance because, to date, modern technologies have not succeeded in producing high-resolution fluorescence images from this depth because of the strong scattering of light.

The Munich researchers say that they can reveal genetic expression within live fly larvae and fish by "listening to light". They believe that this technology may also facilitate the examination of tumours or coronary vessels in humans in future.

Professor Vasilis Ntziachristos, director of the Institute of Biological and Medical Imaging of the Helmholtz Zentrum Munchen, has revealed that the new technology being used by his team can render three-dimensional images through at least six millimetres of tissue, allowing whole-body visualization of adult zebra fish.

To achieve this feat, he and his colleagues made light audible.

The researchers illuminated the fish from multiple angles using flashes of laser light that are absorbed by fluorescent pigments in the tissue of the genetically modified fish.

They say that the fluorescent pigments absorb the light, a process that causes slight local increases temperature, which in turn result in tiny local volume expansions.

According to them, this happens very quickly and creates small shock waves, and the short laser pulse in turn gives rise to an ultrasound wave that the researchers pick up with an ultrasound microphone.

An attached computer uses mathematical formulas-specially developed to analyse the resulting acoustic patterns-to evaluate and interpret the specific distortions caused by scales, muscles, bones and internal organs to generate a three-dimensional image.

The researchers say that this "multi-spectral opto-acoustic tomography" (MSOT) results in an image with a striking spatial resolution better than 40 micrometers.

What is interesting in the fact that the sedated fish wakes up and recovers without harm after the procedure.

"This opens the door to a whole new universe of research. For the first time, biologists will be able to optically follow the development of organs, cellular function and genetic expression through several millimeters to centimeters of tissue," Nature magazine quoted Dr. Daniel Razansky, who played a pivotal role in developing the method, as saying.

Bio-engineer Ntziachristos is convinced that "MSOT can truly revolutionize biomedical research, drug discovery and healthcare."

Ntziachristos says: "Since MSOT allows optical and fluorescence imaging of tissue to a depth of several centimeters, it could become the method of choice for imaging cellular and subcellular processes throughout entire living tissues."

A research article describing the novel technique has been published in the journal Nature Photonics. (ANI)

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