Organoids are three-dimensional (3D) miniature structures cultured in vitro produced from either human pluripotent stem cells (hPSCs) or adult stem cells (AdSCs) derived from healthy individuals. Laboratory of Stem Cell Bioengineering, Institute of Bioengineering, School of Life Sciences (SV) and School of Engineering (STI), cole Polytechnique Fdrale de Lausanne (EPFL), Lausanne, Switzerland, Institute of Chemical Sciences and Engineering, School of Basic Science (SB), cole Polytechnique Fdrale de Lausanne (EPFL), Lausanne, Switzerland, You can also search for this author in PLoS ONE 9, e107814 (2014). & Knoblich, J. J. Physiol. Alternatively, primary explanted cells can be used to model mammalian tissues in vitro. 7, 10243 (2016). Therefore, next-generation engineered materials are expected to further expand the plethora of organoids that can be grown in vitro and increase the developmental robustness of already established cultures. Poor robustness of growth and patterning are major limitations of organoids, resulting in highly heterogeneous end-point collections. 15, 701706 (2009). [60] S. F. Roerinket al., Intra-tumour diversification in colorectal cancer at the single-cell level,Nature, vol. That technologythe ability to grow organoidsis becoming a reality and is finding new uses every day, in part thanks to the work of scientists at the Harvard Stem Cell Institute. Organoids are better at representing cellular environments found in vivo than conventional two-dimensional (2D) cell cultures. [1] M. A. Lancaster and J. PLoS Pathog. Biomicrofluidics 8, 024106 (2014). 21, no. Routinely used setups mainly use optical monitoring as readout, which provides only little information about the functionality of the organoids. Genome editing could be employed to modify the intrinsic response of cells in an organoid to external stimuli with the aim of generating cell types that would otherwise be absent. Commun. & Sun, J. Salmonella-infected crypt-derived intestinal organoid culture system for hostbacterial interactions. The cell population of an organoid can also be characterized using flow cytometry and bulk gene expression assays. Organoids grow from stem cellscells that can divide indefinitely and produce different types of cells as part of their progeny. Morphogenesis guided by 3D patterning of growth factors in biological matrices. Stange, D. E. et al. 29, pp. Stem Cell Rep. 10, 12671281 (2018). 26612670, 2017, doi: 10.1016/j.celrep.2017.11.005. Such microfabrication-based devices provide the opportunity to combine biophysical and biochemical stimuli and, thus, increase the physiological relevance of in vitro models and the robustness of their generation protocols. Sato, T. et al. Organoid culture can then be evaluated based on morphology by taking measurements to quantify variables such as shape and area [36]. Owing to their closed cystic architecture and their continuous expansion, organoids, for example, gastrointestinal organoids, need to be regularly broken up and reseeded to new cultures, which makes them inherently incompatible with long-term studies. 1, pp. & Liu, F. Organoids to study immune functions, immunological diseases and immunotherapy. Pluripotent stem cell (PSC)-derived organoids are an invaluable model system for developmental biology; for example, human-specific features of neurodevelopmental processes were discovered by analysing brain organoids from human and non-human primates at a single-cell level219,220. Google Scholar. Cell 126, 677689 (2006). Table 1: Growth factors and small molecule inhibitors used in organoid production [25]. Wnt/-catenin promotes gastric fundus specification in mice and humans. In the past decade, a new model system has been gaining steam in neurosciencethe brain organoid. At a more fundamental level, genetically engineering the behaviour of cells can increase the functional relevance of organoids, for example, by tailoring responses to specific experimental stimuli or by driving differentiation of rare cell types. Building on these insights, efforts were made to establish large-scale production methods of liver buds derived from human PSCs of up to 108 cells [41], and long-term culturing methods for liver organoids [48]. 339351. Assembly of functionally integrated human forebrain spheroids. Similarly, the mechanical properties of ECMs constantly change during intestinal organoid development131, which could be addressed by introducing light-mediated changes of the mechanical properties of synthetic growth matrices, for example, using photodegradable hydrogels. Cell Stem Cell 20, 385396.e3 (2017). Clevers, H. Modeling development and disease with organoids. Organ-on-a-chip-like devices also allow the growth of epithelia on 2D membranes with microfluidic channels on both apical and basal sides, providing bilateral accessibility and the ability to apply fluid flow164,165,166. Daly, A. C., Davidson, M. D. & Burdick, J. Lu, D. & Kassab, G. S. Role of shear stress and stretch in vascular mechanobiology. Breault goes one step further and hints at the possibility of producing organoids from patient derived iPS cells that could be transformed into insulin-producing beta-like cells. 52, e6 (2019). Derivation of human midbrain-specific organoids from neuroepithelial stem cells. Organoids: A new window into disease, development and discovery 87, 10151027 (2018). Flow-enhanced vascularization and maturation of kidney organoids in vitro. Biotechnol. Reducing this variability will be essential to fully capitalize on the potential of organoids in disease modelling, drug screening and regenerative medicine. 11, 347358 (2016). Organogenesis is driven by the intrinsic capacity of stem cells to organize themselves and their progeny. Furthermore, all sensors are directly linked to a processing computer, which actuates the sensors and pneumatic valves for fluidic control, demonstrating the possibility of fully automated culture platforms. Human pluripotent stem cell-derived acinar/ductal organoids generate human pancreas upon orthotopic transplantation and allow disease modelling. Accordingly, brain organoids, for instance, are mimicking a fetal brain phenotype and further efforts reinforcing maturation are required to obtain a faithful model of the adult brain70,96. Acad. 1, pp. 18, 573584 (2017). Thus, only the fine-tuning of controllable parameters (for example, choice of cytokines and matrix composition) may not suffice to overcome these limitations. Understanding biological regulation through synthetic biology. Acad. M.P.L. Gabriel, E. et al. These techniques include high-resolution microscopy, histology, immunofluorescence, and bulk gene expression assays [28]. Cell Rep. 21, 26612670 (2017). [30] T. Grabingeret al., Ex vivo culture of intestinal crypt organoids as a model system for assessing cell death induction in intestinal epithelial cells and enteropathy,Cell Death Dis., vol. Create time-lapse videos that can be accessed in real-time. 291, 37593766 (2016). 175, no. Development 144, 10451055 (2017). The presented device contains multiple compartments for simultaneous growth of different organoids, as well as sensors to monitor various biological (for example, metabolites and biomarkers) and biophysical (temperature, pH and oxygen levels) parameters. Nature 584, 535546 (2020). Similar experiments could be performed to establish various relevant disease models in vitro and to highlight or identify causal effects of specific genes on congenital or acquired pathologies. 437462, 2018, doi: 10.1038/s41586-018-0024-3. In addition, Matrigel is animal-derived, which hampers translation to clinical settings. & Huch, M. Disease modelling in human organoids. Broutier, L. et al. In disease modeling, organoids generated from human cells can overcome several limitations of animal models [1]. Bertaux-Skeirik, N. et al. Biomaterials 32, 39213930 (2011). Zhang, Y.-G., Wu, S., Xia, Y. Organoids often lack key specialized cell types and fail to recapitulate the complexity of native organs, owing to the (partial) absence of a mesenchymal compartment, vascularization and/or microbiome. (A) Bright-field microscopy (BF) imaging and H&E staining (H&E) of cultured PDOs; Immunohistochemistry staining of pan-Cytokeratin (PCK) and caudal-type homeobox 2 (CDX2) to compare staining pattern with matching primary tumours. The disease phenotype of individual patients can also be studied using induced PSC (iPSC)-derived organoids2,5,6; for example, brain organoids have been generated from iPSCs established from patients with microcephaly69,234, AD235,236, PD87,237 or autism spectrum disorders72,75. Learn more about it here. Gao, D. et al. 116, no. Intriguingly, the observed cellular patterning reminiscent of the crypt and villus regions is established even in the absence of externally applied biochemical gradients, highlighting the morphogenic guidance potential of scaffold geometry139. A. Organogenesis in a dish: modeling development and disease using organoid technologies. Jain, R. et al. The organoids were resuspended in 200 l of PBS with 5 g of either HCV KLVALGINAV peptide, non-specific peptide, or no peptide, and incubated at 37C for 1 h. At the end of the incubation period, organoids were washed 2 in . eLife 6, e26575 (2017). Stiffness is a critical niche parameter influencing stem cell behaviour and appears to be the key determinant of the differentiation of mesenchymal stem cells towards different lineages134. As organoids are functional expressions of individual genomes, these cultures are particularly useful to understand how genetic factors contribute to individual disease. Nat. In proof-of-concept studies organoids have been used as tissue grafts for both liver [7] and intestine [8]. 21, 571584 (2020). In vitro organoid models can be derived from cells from a variety of organs, often with astonishing resemblances to their in vivo counterparts, both in terms of microscale tissue architecture and recapitulation of cellular diversity and key functions. Fan, H., Demirci, U. Sci. [56] S. F. Bojet al., Forskolin-induced swelling in intestinal organoids: An in vitro assay for assessing drug response in cystic fibrosis patients,J. Vis. Velazquez, J. J. et al. Nature 539, 560564 (2016). J. Biol. Endoderm-derived epithelial organoids, such as gastrointestinal and respiratory organoids, can also be generated from PSCs6,7. Med. Neurosci. Cerebral organoids model human brain development and microcephaly. A brief history of organoids - PubMed Persistence and toxin production by Clostridium difficile within human intestinal organoids result in disruption of epithelial paracellular barrier function. 22, pp. Artegiani, B. et al. 2, 16022 (2016). Similarly, a heartlungliver model was built using bioprinting and microengineering approaches, allowing inter-organ crosstalk175. In particular, organoids take complex 3D shapes and are embedded in non-homogeneous matrix environments, which, inevitably, leads to optical artefacts. Nat. Breault and Zhou developed a method to transform intestinal epithelial cells into insulin-producing beta cells and tested their method on intestinal organoids. Although organoids can be made more robust and more physiologically relevant by using engineering approaches, they will probably never be as robust and reproducible as cell-line-based models, nor will they be able to fully reproduce the complexity of animal models. Eiraku, M. et al. Thank you for visiting nature.com. Buskin, A. et al. This review summarizes human organoid and supporting technologies . Electrochemical sensors are, indeed, accurate and versatile, but their pervasive use in organoid culture systems is hampered by their bulky nature, and miniaturized versions have only recently been integrated194. Organoid systems also suffer from considerable variability in organoid formation efficiency, end-point morphology and function, which is often inherent to the stochastic nature of in vitro self-organization and cell fate choices. Zhang, W. et al. Boj, S. F. et al. Rev. A. The presence of fluid flow not only improves the maturation of the kidney organoids, including tubular and glomerular compartments, but also favours the generation of a vascular network with perfusable lumens (Fig. Commun. Acta Biomater. J. Natl Cancer Inst. 1, pp. Nat. Frontiers | Human Organoid and Supporting Technologies for Cancer and Nakano, T. et al. Modeling amyloid beta and tau pathology in human cerebral organoids. 6, pp. Cancer, vol. Owing to the different affinities for cellcell binding, a three-layer self-organized structure with autonomous symmetry breaking and cell type divergence is formed. Nat. Controlled cell aggregation is usually achieved by microwell structures or microfluidic devices; alternatively, the surface of cells, that is, the cell membrane, can be modified to improve or initiate cell clustering101. 35, 659666 (2017). Nat. Front. Many lung diseases seem to us like a failure of stem cells, where they are not being able to repair damage, said Kim. A variety of workflows have been developed to generate organoids; however, specialized organoid types require unique culture methods, and not all general workflows are appropriate. Nephrol., vol. 1, pp. 3D bioprinting of high cell-density heterogeneous tissue models through spheroid fusion within self-healing hydrogels. 1, p. 116, 2018. 21, 941951 (2018). 113, 2017, doi: 10.1172/jci.insight.86492. The field of organs-on-a-chip has been landmarked by the lung-on-a-chip device established by Dongeun Huh et al.164, which was then further adapted to model other organs, such as the intestine and kidneys165,166. High-throughput automated organoid culture via stem-cell aggregation in microcavity arrays. Rep. 4, 6313 (2014). An impressive degree of physiologic functionality has been achieved in intestinal (mucus production and absorptive activities), gastric (histamine-inducible acidification), hepatic (albumin expression, glycogen accumulation and low-density lipoprotein uptake) and mammary gland organoids (milk production)21,30,47,84; however, none of the established organoid systems reproduces the full functional repertoire of their respective organ. Opthalmol. A. Fused cerebral organoids model interactions between brain regions. Organoids developed from human pluripotent stem cells (PSCs) are particularly useful for engineering tissues for which cell retrieval is impractical, such as the brain or retina4,7. Taurino, I. et al. Derivation of a robust mouse mammary organoid system for studying tissue dynamics. Engineered human pluripotent-stem-cell-derived intestinal tissues with a functional enteric nervous system. [27] S. Florian, Y. Iwamoto, M. Coughlin, R. Weissleder, and T. J. Mitchison, A human organoid system that self-organizes to recapitulate growth and differentiation of a benign mammary tumor,Proc. Nat. & Takayama, S. Integration of sensors in gastrointestinal organoid culture for biological analysis. For example, organoids grown in chemically defined microfilament scaffolds adopt an elongated shape, which leads to the reproducible generation of a neuroectoderm and, ultimately, to improved cortical development compared with standard organoids generated from spherical aggregates140. Woo, D. et al. A microengineered collagen scaffold for generating a polarized crypt-villus architecture of human small intestinal epithelium. Rep., vol. Development 144, 958962 (2017). Leslie, J. L. et al. Muguruma, K., Nishiyama, A., Kawakami, H., Hashimoto, K. & Sasai, Y. Self-organization of polarized cerebellar tissue in 3D culture of human pluripotent stem cells. Med., vol. Adv. 6194, 2014,doi: 10.1126/science.1247125. Nikolaev, M. et al. Normal, cancer, or genome-modified organoids can be used for evaluating whether specific chemicals possess genotoxic or non-genotoxic carcinogenic activity by assessing the rate of cancer incidence, progression, and metastasis. M.P.L.s work in the area of organoid biology and technology is supported by the Swiss National Science Foundation (#310030_179447), cole Polytechnique Fdrale de Lausanne (EPFL), the European Unions Horizon 2020 research and innovation programme (INTENS, #668294), the Personalized Health and Related Technologies initiative from the ETH Board, the National Center of Competence in Research (NCCR) Bio-Inspired Materials, the FreeNovation funding program of the Novartis Research Foundation, the Marie Skodowska-Curie European Training Network EUROoC (H2020-MSCA-ITN-2018) and the Vienna Science and Technology Fund (WWTF). Spatiotemporal control over the presentation of biochemical cues can also be achieved by direct patterning of the growth matrix using engineering methods, which allow greater macroscale control compared with microfluidic-induced gradients127. This has been achieved by first differentiating human PSCs into different brain region-specific organoids separately, and then fusing them together in a controlled manner to form assembloids [3]. Stem Cell Rep. 8, 11441154 (2017). Burkitt, M. D., Duckworth, C. A., Williams, J. M. & Pritchard, D. M. Helicobacter pylori-induced gastric pathology: Insights from in vivo and ex vivo models. 4, no. Sci. Brassard, J. Cell 48, 751763 (2019). Sun, D., Evans, L. D. & Rawlins, E. L. Organoid Easytag: an efficient workflow for gene targeting in human organoids. The integration into a microfluidic device allows the growth for extended periods of time. Zhou, J. et al. Cell Biol. 274-283.e5, 2017, doi: 10.1016/j.stem.2017.06.017. Interestingly, by introducing a second synNotch receptor in the first cell population, the crosstalk between the two populations leads to self-sorting. Shin, S. R. et al. Now we can create organoids from diseased cells and conduct experiments to find out if stem cells or the helper cells that talk to them are at the cause of lung disease. Progenitor identification and SARS-CoV-2 infection in human distal lung organoids. Brandenberg, N. et al. Indeed, typical hydrogel domes containing many organoids are rather impractical for the incorporation of biosensor electrodes. This work reports a multi-organ microfluidics platform with automated and continuous monitoring of cultured organoids. Kim uses a similar approach to study the reverse of that question: what happens in diseases where stem cells either fail at their job or create defective cells? [5] T. Satoet al., Single Lgr5 stem cells build crypt-villus structures in vitro without a mesenchymal niche,Nature, vol. The ECM in the stem cell niche is an important parameter for stem cell self-renewal and differentiation, and alterations in ECM composition are a hallmark of many diseases123,124. A two-organoid microfluidic device (containing cardiac and hepatic organoids) has been equipped with multiple integrated physical, biochemical and optical sensing capabilities195 (Fig. Organoids: Types, Studies and Ethical Use | Disabled World New York, NY: Springer New York, 2019, pp. Gastroenterology 141, 17621772 (2011). In the meantime, to ensure continued support, we are displaying the site without styles Finally, the use of cell lines reduces the physiological relevance of organs-on-a-chip compared with organoids. Natl. [3] X. Qian, H. Song, and G. Ming, Brain organoids: advances, applications and challenges,Development, vol. Kidney organoids from human iPS cells contain multiple lineages and model human nephrogenesis. Curr. Commun., vol.