What Are Spheroids?
A spheroid is a small, spherical cluster of cells that acts as a 3D cell culture. The term “organoid” is also used interchangeably with “spheroid”, although the former specifically refers to a 3D cluster of organ-specific cells. Spheroids and organoids can be artificially assembled through different methods, including the use of centrifugal force or gravity. As the spheroid forms, cells will sort themselves into different regions and layers of the cluster, mimicking natural processes. Cells adhere to each other and exhibit an organic cell shape and architecture. These cells exchange nutrients and other signals with each other, creating natural environmental gradients throughout the spheroid. Spheroids are useful in drug development research, because researchers can examine the drug’s ability to penetrate into a 3D arrangement of cells, and assess how this might affect resistance to the drug. Cancer research has benefited greatly from spheroids, which can mimic natural tumor-stromal interactions.
Precision Histology for Spheroids
Spheroids and organoids provide researchers an in vitro model that more accurately simulates an in vivo environment. These cell clusters are very small (200µm – 800µm in diameter), and can therefore be mechanically challenging to work with.At Reveal Biosciences, we have built a wealth of expertise for conducting quantitative histopathology on spheroids. We have developed methods to consistently embed, section, and mount spheroids onto glass slides. Routine histochemical stains such as hematoxylin and eosin (H&E) is useful for viewing the structure and overall layout of cells within a spheroid. Masson’s Trichrome or Picrosirius Red stains are helpful tools to observe the buildup of collagen fibers between cells. An in situ hybridization assay can localize specific mRNA sequences within the spheroid cells, and TUNEL can provide information about cell death. Finally, immunohistochemistry (IHC) or immunofluorescence (IF) can identify specific proteins that are being expressed by cells within the spheroid. Reveal offers over 250 optimized IHC protocols including antibodies such as Ki67, Cleaved Caspase-3, and many other cell type-specific biomarkers to assess protein expression on spheroids and organoids.
Quantitative Image Analysis
Once stained, spheroids can be scanned into whole slide images in either bright field or fluorescence, and viewed in the cloud. Our expert computational team will then utilize our deep learning-based models to generate reproducible, quantitative data from spheroid images on a cell-by-cell basis. Spheroids and organoids are extremely versatile models of cells within a living organism, and they can be used to gain insight into a wide range of different research questions.
Contact us to learn how we can apply these methods to your samples.
References
Achilli, Toni-Marie, Julia Meyer, and Jeffrey R. Morgan. “Advances in the formation, use and understanding of multi-cellular spheroids.” Expert opinion on biological therapy 12.10 (2012): 1347-1360
By:
Jeremy Warner, Scientific Marketing Associate, Reveal Biosciences
