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2.3. DNA microbeads for spatiotemporal regulation microscopy revealed that the presence and breakdown of
in organoids the DNA beads do not disrupt the normal development
or cell-type composition of the organoids, confirming the
The regulation of organoid development through matrix biocompatibility of the technology. Using retinal organoids
materials involves the precise design and adjustment of (ROs) derived from zebrafish and early embryos, the study
ECM composition, structure, and physical properties, demonstrated that DNA microbeads could be integrated
which directly influence the formation, differentiation, and into embryos and organoids through microinjection and
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functional performance of organoids. The ECM not only non-invasively erased using light. This mechanism involves
provides essential support and a 3D growth environment the incorporation of a PC segment at the center of DNA
for cells but also regulates cellular behaviors, migration, linkers, allowing nearly instantaneous, spatiotemporal
proliferation, and gene expression through interactions disassembly of DNA microbeads upon exposure to 405 nm
with cell-surface receptors. By controlling the hardness, light (PC-modified DNA microbeads). The light-triggered
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porosity, surface chemistry, and bioactivity of matrix disassembly of PC-modified DNA microbeads occurs not
materials, researchers can fine-tune the developmental only in bulk solution but also in injected ROs. Consequently,
processes of organoids, enabling them to more closely PC-modified DNA microbeads enable non-invasive
mimic the morphology, function, and tissue characteristics removal after tissue integration (Figure 4). By conjugating
of native biological tissues. 24 recombinant Wnt with DNA microbeads, spatiotemporal
The lack of spatial organization of morphogen gradients control over morphogen release at the microinjection site was
is one of the critical factors limiting organoids from fully demonstrated, resulting in the formation of retinal pigment
replicating the corresponding organs, thereby hindering epithelium while preserving neural retina cell types. This
their development as physiologically relevant model study highlights that DNA microbeads, with their cell-sized
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systems. Morphogen gradients are typically achieved dimensions and high stiffness adaptability, can be integrated
through methods such as microfluidic devices and hydrogel into organoids through microinjection, enabling the non-
patterning technologies incorporating biochemical invasive release of their cargo upon light activation. This
signals. 26,27 However, these approaches primarily provide technology provides spatial and temporal control in organoid
unidirectional gradients from the exterior to the interior bioengineering, facilitating morphogen delivery from
of the organoid, exposing outer cells to higher morphogen internal sources throughout development. It holds promise to
concentrations, whereas inner cells are exposed to lower address the demand for implementing morphogen sources in
concentrations. To create spatially discrete morphogen 3D organoid cultures at any stage of development.
sources within organoids and reverse the gradient, 3. Breakthrough mechanistic insights based
previous studies have explored the co-aggregation of
micro/nanoparticles during the assembly of early organoid on organoids
spheres. Using stem cell aggregate fusion techniques, Organoids with enhanced functionality have opened new
extensive spatial control over morphogen release mediated frontiers in exploring disease mechanisms, modeling
by microparticles has been achieved in fused aggregates. hereditary disorders, and uncovering developmental
However, this technique lacks precise and direct spatial or processes. By incorporating diverse functional cell
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temporal control and is limited to optimizing early organoid types and mimicking complex tissue environments, these
assembly, with minimal applicability to mid- and late-stage advanced organoids provide powerful tools to replicate
organoid culture. Therefore, improved methods to initiate and the pathophysiology of genetic diseases. They enable
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regulate morphogen gradients, as well as novel and broadly researchers to identify therapeutic targets by simulating
applicable morphogen delivery technologies, are required. the effects of specific mutations, offering insights into
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Afting et al. introduced nanostructured DNA microbeads personalized treatments. In addition to disease modeling,
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with tunable stiffness that emulate tissue organization to functional organoids facilitate the study of developmental
enable spatiotemporal control of morphogen gradients within mechanisms, revealing critical pathways and cellular
organoids at any developmental stage. DNA bead technology dynamics during organ formation. These breakthroughs
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uses light-sensitive DNA linkers that enable controlled, non- not only deepen our understanding of human biology but
invasive disassembly of the beads when exposed to 405 nm also pave the way for innovative approaches in regenerative
light. These linkers contain photocleavable (PC) groups that medicine and therapeutic discovery.
break down upon ultraviolet light exposure, causing the DNA
beads to lose their fluorescent signal within about 25 – 30 min. 3.1. Organoids loaded with functional cells for
This mechanism allows for precise removal of the beads exploring disease mechanisms
when necessary. Importantly, experiments showed that this Organoids loaded with functional cells for exploring
light-triggered disassembly does not harm the surrounding disease mechanisms represent an advanced and innovative
cells or organoids. Immunofluorescence staining and confocal approach to biomedical research. By incorporating
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Volume 1 Issue 2 (2025) 6 doi: 10.36922/OR025040005