Going deeper than microscopy: the optical imaging frontier in biology

Abstract

Optical microscopy has been a fundamental tool of biological discovery for more than three centuries, but its in vivo tissue imaging ability has been restricted by light scattering to superficial investigations, even when confocal or multiphoton methods are used. Recent advances in optical and optoacoustic (photoacoustic) imaging now allow imaging at depths and resolutions unprecedented for optical methods. These abilities are increasingly important to understand the dynamic interactions of cellular processes at different systems levels, a major challenge of postgenome biology. This Review discusses promising photonic methods that have the ability to visualize cellular and subcellular components in tissues across different penetration scales. The methods are classified into microscopic, mesoscopic and macroscopic approaches, according to the tissue depth at which they operate. Key characteristics associated with different imaging implementations are described and the potential of these technologies in biological applications is discussed.

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Figure 1: Simplified metrics of photon propagation in tissue.
Figure 2: The penetration depth and resolution of modern photonic imaging techniques is depicted.
Figure 3: Principle of operation of SPIM.
Figure 4: Hybrid optical tomography using priors.
Figure 5: Principle of operation of volumetric optoacoustic tomography.
Figure 6: Examples of mesoscopic imaging.

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Acknowledgements

I acknowledge investigators and students for their multiple contributions in understanding optical and optoacoustic performance; J. Ripoll for the contribution of Figure 1b; and support from a European Research Council Senior Investigator Award, the German Federal Ministry of Education and Research and the Institute for Biological and Medical Imaging

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Correspondence to Vasilis Ntziachristos.

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Ntziachristos, V. Going deeper than microscopy: the optical imaging frontier in biology. Nat Methods 7, 603–614 (2010). https://doi.org/10.1038/nmeth.1483

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