Abstract
Organoids are the emerging miniature 3D models that recapitulate the complex cellular heterogeneity, structure, and functions of the native tissues. Organoids have gained huge interest in the development of tissue/disease models, cell therapy, drug screening, and personalized medicine. Although utilized in various applications, the conventionally fabricated organoid models still lack cellular organization. They have a limited lifespan, nutrient exchange, reproducibility, and complex protocols that restrict their translation. The development of miniature models has reached significant heights using functional biomaterials, especially hydrogel, which mimics the native extracellular matrix with tailored mechanical and chemical properties. The hydrogel has been developed through various fabrication techniques like hanging drops, nonadherent cell culture plates, scaffold-based organoids culture, 3D and 4D bioprinted organoids, and microfluidic organoids. The advanced technology thus provides a platform for researchers to develop hydrogel-based miniature organoids as clinically relevant models for future therapeutics. This chapter delves into the evolution of conventional 3D organoids and their limitations, followed by factors that need to be considered for the development of hydrogel-based organoids and their fabrication methods toward biomedical applications.