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capabilities of cartilage after injury but also increases the composed of alginate or decellularized ECM, provide a
difficulty of constructing cartilage organoids. mechanical environment that allows cells to proliferate and

Different from bone organoids, cartilage organoids are differentiate into cartilage tissue, producing new hyaline
composed solely of chondrocytes derived from multiple cartilage with properties similar to natural cartilage.
cellular sources, including isolated and cultured stem cells, Inspired by the structure of cartilage tissue, researchers
namely, ESCs, iPSCs, mesenchymal stem cells (MSCs), have successfully constructed highly biomimetic cartilage
PDCs, and other stem cell or pluripotent cell lines, as organoids by regulating the orientation of collagen fibers
well as chondrocytes derived from autodigestion. 143-146 through plastic compression and introducing a gradient of
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Abe et al. demonstrated successful integration of iPSC- chondroitin sulfate. These organoids not only replicate
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derived cartilage organoids in primate knee joint defect the various heterogeneous features of natural cartilage but
models, with subsequent remodeling into functional also achieve region-specific regeneration of cartilage tissue.
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articular cartilage. Another study by Sun et al., who In addition, the construction of hypoxic cartilage organoids
applied synovial mesenchymal stromal cells to generate provides an important model for studying the hypoxia
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3D-cultured organoids for pre-clinical modeling and adaptation mechanisms of chondrocytes. Yang et al.
treatment of degenerative joint disease. In addition, have used a hyperdynamic hydrogel to construct cartilage
Hall et al. compared two types of cartilage organoids organoids, which exhibit significant accumulation of lactate
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constructed from human PDCs (hPDCs) and iPSCs. The and histone lactylation in a hypoxic microenvironment,
results revealed that the cartilage organoids derived from thereby promoting the proliferation and differentiation of
hPDCs were more similar to hypertrophic cartilage. In chondrocytes.
contrast, the cartilage organoids obtained from iPSCs 3D bioprinting has emerged as a transformative
exhibited ratios of acidic GAGs and aggrecan to total technology in cartilage organoid research, enabling
collagen that more closely resembled natural cartilage. precise spatial control over cellular organization and
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At present, there are mainly two types of organoid ECM composition. This advanced technique not
culture methods: Scaffold-based and scaffold-free. The only facilitates precise control over the layer-by-layer
construction of scaffold-free cartilage organoids primarily deposition of cells, matrix materials, and bioactive factors
relies on the self-organization ability of cells. By placing but also permits the construction of complex structures
cells in a suspension culture environment, cell aggregation that closely recapitulate native cartilage morphology and
is promoted to form 3D structures. This method is simple biomechanical properties. Noteworthy applications include
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and highly reproducible, allowing the rapid generation the work of de Melo et al. and Xie et al., who employed
of organoids without the external scaffold materials. suspension 3D printing technology to fabricate cartilage
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Yamashita et al. demonstrated successful generation organoids through cell-laden microspheres. Recent
of hyaline cartilage organoids from PSCs using scaffold- advances in structural engineering have further enhanced
free suspension culture. In addition, O’Connor et al. organoid fidelity through the development of compression-
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developed a sequential differentiation protocol employing based techniques that induce anisotropic collagen fiber
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transforming growth factor (TGF)-β and BMP to model alignment within hydrogel scaffolds. Concurrently,
the cartilage-bone interface, thereby providing a well- gradients of varying concentrations of chondroitin sulfate
established platform for studying the region between have been established to mimic the composition of
cartilage and bone. In addition to static cultures, centrifugal cartilage. The integration of CRISPR/Cas9 has expanded
cultures without scaffolds have been used for the study of the experimental utility of these systems, as demonstrated
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cartilage organoids. For instance, Irie et al. utilized hollow by Wei et al. through the creation of dual-fluorescence-
fibers as cell culture devices, inducing chondrocytes to form labeled chondrogenic organoids. These cartilage organoid
cylindrical organoids through centrifugation. Steinwerth models offer a robust platform for investigating cartilage
et al. investigated scaffold-free 3D chondrogenic pathologies and advancing regenerative strategies.
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organoid formation in a rotating wall vessel bioreactor 3.3. Skeletal muscle organoids
under simulated microgravity. These results demonstrated
that chondrocytes were able to form dense 3D cartilage- The construction of skeletal muscle organoids first requires
like tissues without the addition of scaffolds. In contrast, the precise reproduction of the cellular composition of
scaffold-based culture methods can select scaffolds with skeletal muscle tissue, which is primarily composed of
corresponding properties according to the purpose of the muscle cells. Current methodologies employ multiple
cartilage organoids. For example, compared with elastic cellular sources for organoid generation, including iPSCs,
hydrogels, viscoelastic hydrogels can better support the myoblasts, satellite cells, MSCs, and in vitro-derived
growth and expansion fusion of cartilage organoids. satellite cells (idSCs). iPSCs represent a particularly
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The viscoelastic hydrogels prepared by Crispim et al., versatile option, as they can be directed through staged
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Volume 1 Issue 3 (2025) 9 doi: 10.36922/OR025280024