Fluorescence confocal imaging via holographic endo-microscopy

0568616 - ÚPT 2023 CZ eng A - Abstrakt
Tučková, Tereza - Pikálek, Tomáš - Jákl, Petr - Turtaev, S. - Šiler, Martin - Ondráčková, Petra - Krejčí, Jana - Uhlířová, Hana - Čižmár, Tomáš
Fluorescence confocal imaging via holographic endo-microscopy.
16th Multinational Congress on Microscopy, 16MCM, 04-09 September 2022, Brno, Czech Republic. Book of abstracts. Brno: Czechoslovak Microscopy Society, 2022 - (Krzyžánek, V.; Hrubanová, K.; Hozák, P.; Müllerová, I.; Šlouf, M.). s. 278. ISBN 978-80-11-02253-2.
[Multinational Congress on Microscopy /16./. 04.09.2022-09.09.2022, Brno]
Grant CEP: GA MŠMT EF15_003/0000476
Institucionální podpora: RVO:68081731 ; RVO:68081707
Obor OECD: Optics (including laser optics and quantum optics)
https://www.16mcm.cz/wp-content/uploads/2022/09/16MCM-abstract-book.pdf

In biological research, there is a desire to image and study cellular processes in deep areas of the tissue. The tissue has strong scattering properties that limit the imaging depth when using light microscopy. The ability to relay light into deeper regions of the tissue has motivated the development of different types of endoscopes based on GRIN lenses, fiber bundles, or multi-mode fiber (MMF). Among those, the MMFs provide the best ratio between resolution and probe diameter. Thus they enable far-most atraumatic way of imaging up to unprecedented depth in the living brain tissue while achieving diffraction-limited resolution. However, the MMF acts as a turbid medium and the light after propagation comes out in a form of a random scrambled pattern. In order to counteract this scrambling, the light coupled into MMF can be modulated by spatial light modulators. In our case of MMF-based holographic endoscopy, the light is modulated using a digital micro-mirror device. At the distal end of the fiber, a single diffraction-limited spot is thus generated. This modulation enables imaging of the sample by scanning the spot across the field of view in the focal plane, similarly to a scanning microscope, and excites the fluorescence signal which is then collected by a bucket detector (PMT). However similarly to classical single photon excitation fluorescence microscopy, the images obtained through the MMF suffer from a decrease in contrast and resolution due to light scattered from out-of-focus planes. This effect is detrimental especially in highly-scattering dense tissue, such as the brain. In classical fluorescent microscopy, the out-of-focus light is suppressed using e.g. confocal approach. In the case of endoscopy, this confocal approach has also been demonstrated. However, it is not optimal for fluorescence in vivo imaging. We introduce a new concept of MMF-based confocal imaging which allows the suppression of out-of-focus light and attenuation of the background signal. As we here present on the imaging of the fluorescent phantom sample and fixed brain slices, confocal filtration increases the contrast and resolution of the resulting images.
Trvalý link: https://hdl.handle.net/11104/0340081