Newswise — There exist diverse methods to visualize biological specimens at a microscopic scale, and each method possesses its own advantages and disadvantages. In a groundbreaking development, a group of scientists, including individuals from the University of Tokyo, have merged elements from two prominent imaging techniques to create a novel approach for imaging and examining biological samples. Termed RESORT, this innovation opens up pathways to observe living systems with unparalleled precision.
Throughout the entire span of human history, since the moment we gained the ability to manipulate glass, optical instruments have been employed to observe the minute realm of the microscopic with progressively enhanced clarity. As our visual capabilities expand, so does our capacity for comprehension, resulting in a constant drive to enhance the tools we employ for exploring both the external and internal world. Modern microscopic imaging methodologies have transcended the limitations of traditional microscopes, offering a myriad of advancements. Among these advancements, two prominent technologies have emerged: super-resolution fluorescence imaging, which delivers impressive spatial resolution, and vibrational imaging, which may sacrifice spatial resolution but compensates with the ability to utilize a wide array of colors to effectively label diverse cellular components.
"We were compelled by the limitations exhibited by these types of imaging methodologies, driving us to strive for a superior solution, and with RESORT, we are confident that we have achieved just that," stated Professor Yasuyuki Ozeki from the Research Center for Advanced Science and Technology at the University of Tokyo. "RESORT, an acronym for reversible saturable optical Raman transitions, combines the advantageous aspects of super-resolution fluorescence imaging and vibrational imaging while avoiding the disadvantages of both. This laser-based technique utilizes a phenomenon called Raman scattering, a unique interaction between light and molecules that aids in the identification of components within a microscopic sample. To verify the efficacy of the technique, we successfully conducted RESORT imaging of mitochondria within cells."
‘RESORT imaging encompasses several distinct stages, and although it may initially appear intricate, its setup is comparatively less complex than the techniques it seeks to supersede. The process involves multiple steps to achieve precise imaging. Firstly, the targeted constituents within the sample under examination are labeled or stained using specialized chemicals known as photoswitchable Raman probes. These probes possess the ability to modulate Raman scattering in response to the various laser lights employed by RESORT. Subsequently, the sample is positioned within an optical apparatus designed to accurately illuminate it and construct an image. This entails subjecting the sample to two-color infrared laser pulses to detect Raman scattering, along with the utilization of ultraviolet light and a distinct donut-shaped visible light beam. Collectively, these elements confine the region where Raman scattering can take place. As a result, during the final stage of imaging, the probe can be precisely detected at an exceptionally fine point, thereby achieving a remarkable spatial resolution.
"It's not solely about obtaining higher-resolution images of microscopic samples; after all, electron microscopes can reveal these entities with far greater detail," Ozeki explained. "However, electron microscopes inherently inflict damage or hinder the samples they scrutinize. In contrast, RESORT has the potential to image numerous components within living samples, capturing them in action and facilitating the analysis of intricate interactions like never before. By further developing the range of colors available for Raman probes, RESORT will enable the visualization of dynamic processes in living samples. This breakthrough will significantly contribute to a deeper comprehension of fundamental biological mechanisms, disease processes, and potential therapeutic interventions."
The primary objective of the team was to enhance microscopic imaging for utilization in medical research and associated domains. However, the progress achieved in laser design could also find application in other laser-based fields, such as materials science, where there is a demand for high power or precise control.
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