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International Journal of Bioprinting DNA-functionalized hyaluronic acid bioink

Figure 3. Hydrogels with functional DNA units. (a) Thermosensitive G-quadruplex-crosslinked copolymer hydrogel with reversible solution–hydrogel–
solid transitions. Reprinted with permission from ref. Copyright © 2015 Royal Society of Chemistry. (b) pH-responsive DNA hydrogel based on 3D
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assembly of Y-shaped DNA nanostructure with interlocking i-motif domains. Reprinted with permission from ref. Copyright © 2009 Wiley. (c) pH-
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activated reversible DNA hydrogels based on triplex structures. Reprinted with permission from ref. Copyright © 2018 Royal Society of Chemistry. (d)
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Plasmid-complex-encapsulated-loaded alginate/HA hydrogel for bFGF delivery. Reprinted with permission from ref. Copyright © 2019 Royal Society
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of Chemistry. (e) ATP aptamer-modified linker and Y-scaffold DNA hydrogel with conformational transition and mechanical properties. Reprinted with
permission from ref. Copyright © 2018 MDPI.
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fluctuations. These changes allow the hydrogel to capture adenine-thymine (T-A-T) base triplets. By adjusting
and release cargo in a regulated manner. By integrating environmental conditions (such as pH), the morphology
this i-motif sequence, which undergoes a pH-dependent and properties of hydrogels can be controlled. The C-G-C+
conformational change, into the DNA hydrogel network, triplexes are formed at a pH of 5.0 and disassemble at a pH
microscopic transitions occur, leading to significant of 7.0, while the T-A-T triplexes are formed at a pH of 7.0
changes in the mechanical properties of the hydrogel. and disassemble at a pH of 10.0. These triplex structures
Consequently, this strategy enables the reversible control afford the DNA structures the ability to perform pH-
of the hydrogel’s mechanical strength, ranging from 250 Pa regulated reversible self-assembly, which allows it to switch
to 1000 Pa, proving beneficial for applications such as cell between gel and liquid phases (Figure 3c).
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differentiation and tissue engineering.
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2.2.4. DNA plasmid
2.2.3. Triplex structures Among its primary utilities, plasmids are instrumental in
The formation of triplex structures relies on the protonation the field of recombinant DNA technology. This technique
of cytosine-guanine-cytosine (C-G-C+) and thymine- involves the integration of foreign DNA sequences into

Volume 10 Issue 2 (2024) 31 doi: 10.36922/ijb.1814