Organoids: Applications and challenges of advanced hydrogels in tissue systems

Repair and regeneration of tissues and organs remain central to medical research. Organoids, advanced models created through in vitro tissue engineering, enable stem cells to form three-dimensional structures that replicate organ tissues and function spontaneously. The advancement of organoid technology has greatly enhanced our understanding of disease progression and organ development. A crucial component of this technology is the development of appropriate scaffolds to support organoid growth. Recently, hydrogels have emerged as promising materials due to their excellent biocompatibility, tunability, and degradability, facilitating the in vitro culture of stem cells and their differentiation into various organoids. However, more complex organ models, which involve extensive intercellular and extracellular communication, present significant challenges for present research. Moreover, advancements in biomaterial fabrication and their integration with organoid technology remain underexplored. This review explores the pivotal role of hydrogels in organoid preparation, comparing the advantages and limitations of different hydrogel fabrication methods. It also highlights recent advancements in the application of organoid hydrogels across various biological systems and discusses future challenges and directions in this field.