Organoids are simple tissue-engineered cell-based in vitro models that recapitulate many aspects of the complex structure and function of the corresponding in vivo tissue. They can be dissected and interrogated for fundamental mechanistic studies on development, regeneration and repair in human tissues, and can also be used in diagnostics, disease modelling, drug discovery and personalized medicine. Organoids are derived from either pluripotent or tissue-resident stem (embryonic or adult) or progenitor or differentiated cells from healthy or diseased tissues, such as tumours. To date, numerous organoid engineering strategies that support organoid culture and growth, proliferation, differentiation and maturation have been reported. This Primer highlights the rationale underlying the selection and development of these materials and methods to control the cellular/tissue niche; and therefore, the structure and function of the engineered organoid. We also discuss key considerations for generating robust organoids, such as those related to cell isolation and seeding, matrix and soluble factor selection, physical cues and integration. The general standards for data quality, reproducibility and deposition within the organoid community are also outlined. Lastly, we conclude by elaborating on the limitations of organoids in different applications, and the key priorities in organoid engineering for the coming years.

类器官是基于细胞的简单组织工程体外模型，概括了相应体内组织复杂结构和功能的许多方面。它们可以被解剖和询问，用于人体组织发育、再生和修复的基本机制研究，也可以用于诊断、疾病建模、药物发现和个性化医疗。类器官源自健康或患病组织（例如肿瘤）的多能或组织驻留干细胞（胚胎或成体）或祖细胞或分化细胞。迄今为止，已经报道了许多支持类器官培养和生长、增殖、分化和成熟的类器官工程策略。本入门手册强调了选择和开发这些材料和方法来控制细胞/组织生态位的基本原理；因此，工程类器官的结构和功能。我们还讨论了生成强大的类器官的关键考虑因素，例如与细胞分离和接种、基质和可溶性因子选择、物理线索和整合相关的因素。还概述了类器官界内数据质量、再现性和沉积的一般标准。最后，我们详细阐述了类器官在不同应用中的局限性，以及未来几年类器官工程的关键优先事项。