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structures and functions are typically complex and diverse. The developed cardiac organoid, with a controlled ratio
3D bioprinting has been widely studied for creating 3D of myocardial cells and fibroblasts, was able to simulate
scaffolds with intricate structures and specific functions, the structural and functional characteristics of cardiac
making it a powerful tool for optimizing organoid structure tissue after myocardial infarction, including decreased
and function. To mimic the complex cellular composition, contractility and irregular electrical activity.
multiscale spatial structure, and extracellular matrix The dense microvascular network is also an important
characteristics of liver tissue, Jian et al. optimized the feature of the intestine. Li et al. printed bioink containing
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bioink formulation to maintain structural integrity and endothelial cells and composite hydrogel precursors to
manufactured liver organoids with biomimetic lobular form a 3D scaffold with a macro tubular structure and
structures using 3D droplet bioprinting. After seven days of internal circular folding. They then seeded Caco-2 cells
cultivation, the lobular-like structure of the liver organoids
remained intact, displaying characteristics of multicellular onto the internal structure of the scaffold, and, under the
distribution. influence of the structure and the maturation of the internal
endothelial cells, they developed an intestinal construct
The multicellular printing capability of 3D bioprinting, with dense microvasculature and an intestinal epithelioid
coupled with the flexibility of printing programs, greatly structure. Overall, 3D bioprinting offers an effective
benefits the development of hierarchical tissue organoids. approach for the large-scale development of intestinal
For instance, a study developed a skin organoid containing organoids and is valuable for developing organoids with a
human keratinocytes, fibroblasts, and endothelial cells more comprehensive intestinal tissue structure.
through extrusion 3D bioprinting combined with stepwise
photocrosslinking under the influence of a temperature 5. Improving three-dimensional bioprinting
field. This improvement in the preparation process technology for organoid development
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preserved the structural characteristics and mechanical
properties of 3D bioprinted skin organoids, which could be Three-dimensional bioprinting has demonstrated
customized for wound healing applications. considerable advantages in organoid development, inspiring
researchers to explore better methods for leveraging this
In addition to optimizing structure, 3D bioprinting technology to advance organoid applications. Consequently,
has shown significant potential for improving the enhancing 3D bioprinting techniques for organoid
function of organoids. In a study, a 3D scaffold with an development has become a key focus of research. This
elastic modulus matching that of natural heart tissue was section highlights how advancements in 3D bioprinting
designed to form a cardiac organoid model by printing a strategies can foster the development and application of
mixture of cardiomyocytes, fibroblasts, and microvascular organoids.
endothelial cells. In vitro experiments revealed that this
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cardiac organoid model exhibited cardiac-specific cellular 5.1. Developing advanced bioinks
functions, with myocardial cells displaying contractile The physical and chemical properties of bioink directly
activity during cultivation.
influence the behavior of printed cells or organoids. 64-66
4.2. Vascularization of organoids via three- Therefore, an optimized composition of bioinks is
dimensional bioprinting essential for advancing organoid development. Wang
et al. designed a specific bioink composed of pancreatic
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Vascularization is crucial for the development and extracellular matrix and hyaluronic acid methacrylate to
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application of organoids. Fortunately, 3D bioprinting create 3D bioprinted islet organoids. This bioink enhances
provides a method for creating organoids with perfusable the functional characteristics of pancreatic islets in vitro.
vascular functions. Skylar-Scott et al. assembled stem In vivo experiments also confirmed that the hydrogel
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cell-derived organoids into high-density living matrices formed by this bioink regulates insulin levels and promotes
and then introduced perfusable vascular channels into angiogenesis, offering a promising therapeutic approach
them through embedded 3D printing. The resulting cardiac for islet transplantation.
organoids fused and began beating within 7 days (Figure 5).
This manufacturing method not only promotes organoid For tumor organoids, bioinks must not only meet the
growth but also incorporates vascular channels, which are printing performance requirements but also simulate
essential for the functional development of the organoids. the cell-extracellular matrix interactions to accurately
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Furthermore, a heart organoid model was developed replicate the tumor microenvironment. Consequently,
by self-assembling and fusing 3D bioprinted spheres researchers have developed a low-concentration collagen
into high-density microstructures. The self-healing I-based bioink that is compatible with breast tumor cells
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properties of hydrogel microspheres allowed them to fuse and cancer-related fibroblasts. This bioink regulates the
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under controlled conditions to form a stable structure. phenotype and carcinogenic behavior of the cells, and

Volume 1 Issue 1 (2025) 8 doi: 10.36922/OR025040004