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and the formation of elongated epithelium in organoids. proteins, such as laminin, actin, proteoglycan, and growth
Microfluidic devices amplify these effects by providing a factors, which lead to upregulated expression of other
favorable dynamic microenvironment for brain organoid non-specific cell types, such as brain markers FOXA2 and
culture (Figure 6B). FOXG1. In contrast, alginate has the advantage of reducing
COs exhibit morphological and biochemical features the influence of these cofactors, improving the specificity
similar to the human brain, allowing data acquisition closer and scalability of spinal cord organoids (Figure 6D). In
to physiological conditions. Using biologically active and addition, alginate hydrogels can minimize the impact of
stiffness-tunable hydrogels, such as those incorporating shear stress on organoids, preventing their aggregation
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peptides and HA, provides an ideal supportive structure and reducing variability in experimental results. Wang
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that aids the growth and development of organoids. The et al. employed dECM hydrogel from the human placenta
integration of microfluidic devices with the ECM of brain (DPECMH) to promote the development of hiPSC-
cells enhances structural and functional maturation of derived spinal cord organoids with distinct dorsal-ventral
organoids, improves cell viability and proliferation rates, tissue structures. DPECMH prepared through a series of
and promotes neurogenesis. However, some differences processing steps, has a complex ECM composition that
exist between the development of brain organoids and the supports the development and differentiation of spinal cord
human brain, such as neurodevelopment, brain volume, organoids better than traditional Matrigel. It facilitates the
and genomic type, which may impact the reliability of formation of key spinal cord regions within the organoids,
experimental results. Despite simulating certain brain including the floor plate, dorsal interneuron pre-cursor
functions, organoids have not fully reproduced the domain, ventral interneuron pre-cursor domain, and
complexities of the neural network and higher cognitive motor neuron pre-cursor domain. In addition, DPECMH
functions. Therefore, it cannot replace genuine brain promotes the generation of motor neurons, inhibitory
research. Nevertheless, these studies have provided a neurons, and glial cells within the spinal cord organoids.
new platform for investigating neurological disorders The research provides a more comprehensive and accurate
and developing novel therapeutic strategies, necessitating model for spinal cord organoid studies, with the potential
continued technical research and improvements to enhance to advance spinal cord development and pathology
reliability in the future. research. 134
Given the limited regenerative capacity of spinal cord
4.5.2. Spinal cord
neurons, the study of organoids offers new avenues for neural
The initial spinal cord structure is formed during embryonic regeneration. Utilizing alginate hydrogels and DPECMH
development through the preliminary closure of the neural provides enhanced support for organoid development.
tube. The neural tube is divided into the inner grey matter Compared to traditional Matrigel, these hydrogels reduce
and the outer white matter. In the grey matter, clusters of non-specific cell type expression, thereby improving the
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neuronal cell nuclei develop into neurons, while glial cells, specificity and scalability of organoids. However, the
such as astrocytes and oligodendrocytes, begin to form extended growth cycles of spinal cord neurons may result
and support neuronal function by providing nutrition, in slower research progress. In addition, organoids may not
structural support, and forming myelin sheaths. The fully replicate all biological characteristics of human spinal
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white matter is primarily composed of myelinated nerve cords, limiting their effectiveness in certain applications.
fibers. Spinal cord neurons, as permanent cells, have limited Therefore, while organoids provide a novel platform for
regenerative capacity and a long growth cycle. In addition, spinal cord regeneration research, further research and
spinal cord nerve distribution differences between animal technological advancements are necessary to enhance their
and human tissues make in vitro experiments extremely biological relevance and application potential.
challenging. However, emerging techniques for preparing
spinal organoids hold promise for advancing neuroscience. 4.6. Skeletal system
Traditional matrices for organoid culture, such as Bone formation and development involve two primary
basement membrane extracts or Matrigel, have unclear processes: Bone development and remodeling. During
compositions, leading to reproducibility issues in spinal early embryonic development, intramembranous
organoid development. 60,132 To address this, Chooi ossification begins in the periosteum (a connective tissue
et al. proposed using alginate hydrogels as an alternative membrane), where osteoprogenitor cells differentiate into
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(Figure 6C). Research has shown that by adjusting the osteoblasts, which mature into osteocytes and produce
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concentration of alginate, the stiffness of hydrogels bone matrix. The process of endochondral ossification
can be customized, facilitating the study of the effects involves chondrocyte proliferation and differentiation,
of biophysical and biochemical signals on organoid bone mineralization, and chondrocyte apoptosis, ultimately
maturation. Conventional Matrigel contains non-essential forming primary bone. Some bones, particularly
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Volume 1 Issue 2 (2025) 17 doi: 10.36922/or.8262