Cited by 93Advanced Fluorescence Microscopy TechniquesCell Image Analysis Techniques3D Printing in Biomedical Research

Routine Optical Clearing of 3D-Cell Cultures: Simplicity Forward

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Nürnberg, Elina, Vitacolonna, Mario, Klicks, Julia, von Molitor, Elena, Cesetti, Tiziana, Keller, Florian, Bruch, Roman, Ertongur-Fauth, Torsten +7 more·2020·Frontiers in Molecular Biosciences

Abstract

Three-dimensional cell cultures, such as spheroids and organoids, serve as increasingly important models in fundamental and applied research and start to be used for drug screening purposes. Optical tissue clearing procedures are employed to enhance visualization of fluorescence-stained organs, tissues, and three-dimensional cell cultures. To get a more systematic overview about the effects and applicability of optical tissue clearing on three-dimensional cell cultures, we compared six different clearing/embedding protocols on seven types of spheroid- and chip-based three-dimensional cell cultures of approximately 300 μm in size that were stained with nuclear dyes, immunofluorescence, cell trackers, and cyan fluorescent protein. Subsequent whole mount confocal microscopy and semi-automated image analysis were performed to quantify the effects. Quantitative analysis included fluorescence signal intensity and signal-to-noise ratio as a function of z-depth as well as segmentation and counting of nuclei and immunopositive cells. In general, these analyses revealed five key points, which largely confirmed current knowledge and were quantified in this study. First, there was a massive variability of effects of different clearing protocols on sample transparency and shrinkage as well as on dye quenching. Second, all tested clearing protocols worked more efficiently on samples prepared with one cell type than on co-cultures. Third, z-compensation was imperative to minimize variations in signal-to-noise ratio. Fourth, a combination of sample-inherent cell density, sample shrinkage, uniformity of signal-to-noise ratio, and image resolution had a strong impact on data segmentation, cell counts, and relative numbers of immunofluorescence-positive cells. Finally, considering all mentioned aspects and including a wish for simplicity and speed of protocols - in particular, for screening purposes - clearing with 88% Glycerol appeared to be the most promising option amongst the ones tested.

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Crossref · 10.3389/fmolb.2020.00020

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  • Specialized microscopy techniques and tissue processing (e.g., clearing) can overcome challenges in imaging 3D cultures, but they require additional specifications and QC.

    “Specialized microscopy techniques and tissue processing (e.g., clearing) can overcome these challenges, but they require additional specifications and QC (Nurnberg et al., 2020; Renner et al., 2021; Cheng et al., 2023; Yoshida et al., 2020; Kahn-Krell et al., 2022).”

    From Recommendations on fit-for-purpose criteria to establish quality management for microphysiological systems and for monitoring their reproducibility (2024) · cites this paper as Nurnberg et al., 2020

    The Introduction (page unavailable) says whole-mount confocal or light-sheet imaging can circumvent limitations of sectioning, and that clearing improves imaging depth. The Conclusion (page unavailable) says clearing protocols must be chosen according to sample characteristics and that imaging settings affect quantitative analysis. The paper supports the need for method-specific planning, but does not explicitly say these techniques require additional specifications and quality control. (LLM, conf=0.82)

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Authors
Nürnberg, E., Vitacolonna, M., Klicks, J., von Molitor, E., Cesetti, T., Keller, F., Bruch, R., Ertongur-Fauth, T., Riedel, K., Scholz, P., Lau, T., Schneider, R., Meier, J., Hafner, M., & Rudolf, R.
Affiliations
  • Heidelberg University (DE)
  • Merck KGaA, Darmstadt (Germany) (DE)
Corresponding author
Rudolf, Rüdiger
Venue
Frontiers in Molecular Biosciences
Published
2020-02-21
Volume
7
Pages
20-20
ISSN
2296-889X (ISSN-L)
OpenAlex
W3008097711
Cited by
93
References
82
Citations by year
2026: 14 · 2025: 12 · 2024: 16 · 2023: 13 · 2022: 18 · 2021: 16 · 2020: 4
FWCI
6.07
Type
journal article
Language
en
Open access
Locations
  • Frontiers in Molecular Biosciences (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • Bundesministerium für Bildung und Forschung
  • Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg
  • Carl-Zeiss-Stiftung
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Biophysics › Advanced Fluorescence Microscopy Techniques
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Biophysics › Cell Image Analysis Techniques
  • Physical Sciences › Engineering › Biomedical Engineering › 3D Printing in Biomedical Research
Keywords
optical tissue clearing, 3D cell culture, spheroids, organoids, sample shrinkage, signal-to-noise ratio, image segmentation, cell counting, co-culture, drug screening

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