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International Journal of Bioprinting Supramolecular hydrogels as bioinks

upon dissociation. A DNA MNP-functionalized all-DNA intermolecular G-quadruplex were developed for 3D cell
hydrogel exhibits diverse behaviors under the influence of culture applications. The hydrogels rapidly formed under
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a magnetic field, including phase changes, shape distortion, physiological conditions, exhibiting excellent mechanical
physical movements, and neutralized gravitational properties, shear-thinning behavior, and injectability. A
effects. 135,137-139 dendritic DNA-based hydrogel (DDH) was developed with
enhanced mechanical stiffness for the in situ incorporation
A two-component mixing technique was used by Li
et al. to demonstrate a rapidly-formed supramolecular of live cells and thermolabile factors. The hydrogel was
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polypeptide–DNA hydrogel, enabling in situ multi-layer formulated with four single-stranded DNAs at nanomolar
inkjet 3D bioprinting (Figure 6A). The hydrogel rapidly concentrations crosslinked to a tetraethylene glycol core
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forms under physiological conditions, facilitating the without any crosslinkers in isothermal conditions.
merging of printed structures, maintaining the shape The hydrogel offers good mechanical support, high cell
viability, and good cell proliferation (Figure 6D).
without deformation, and enabling cell printing for
tissue engineering applications. These hydrogels offer The incorporation of G-quadruplex, a guanine-
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significant advantages specifically in the following areas: rich region, in DNA/RNA-based hydrogels was
(i) facilitate stem cell differentiation by regulating matrix reported by Aderito et al. The group created an
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mechanical strength alone; (ii) facilitate cell migration injectable, conductive, thermo-reversible, and self-healing
within the hydrogel and establish a realistic in vivo model G-quadruplex hydrogel by combining guanosine (G),
for observing cancer cell migration; (iii) synergize with 3D potassium chloride, and 3-aminophenylboronic acid-
printing technology to enhance the creation of artificial functionalized HA (HA-PBA) in a dynamic co-assembling
organs and 3D tissues. multicomponent system (Figure 6E). The K -stabilized gel
+
was created between G-coupled dynamic covalent boronate
Zhang et al. reported a 3D-nanostructured
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supramolecular hydrogel containing G-quartet/hemin ester bonds and HA-PBA through hydrogen bonding
and π–π interaction. The HA-functionalized GelMA
(G4/H) motifs, GO, and poly(vinyl alcohol) (PVA), microchannel-embedded 3D hydrogel displayed enhanced
synthesized using a direct self-assembly method (Figure
6B). The resulting GO/PVA/G4/H hydrogel displayed cell viability, subsequently applied as artificial blood
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remarkable mechanical strength and a strong 3D GO vessels. The incorporation of nanoforms or nanostructures
network that resembles a honeycomb. Notably, the hydrogel in DNA hydrogel will reinforce the polymer network and
can be utilized as an injectable ink and for 3D printing enhance its physical characteristics. A study detailed that
a variety of patterns due to its reversible pH-induced an injectable 3D-bioprinted scaffold, containing GelMA
and self-assembled tetrahedral DNA nanostructure (TDN),
phase shifts. Enzymes can be used to create responsive successfully delivered an antibiotic, clindamycin (CLI), for
binary AND/OR logic gates and can also be used to detect 142
H O with extreme sensitivity by exhibiting remarkable treating osteomyelitis. The antibiotic was electrostatically
2
2
peroxidase-like activity. This adaptable hydrogel complexed to the TDN network nanocarrier. As a result, the
architecture could advance intelligent soft materials across TDN nanocarrier-loaded GelMA scaffold is biocompatible
various biological and medicinal applications. 129 and suitable for bone tissue regeneration with significant
antibacterial activity.
In another recent study, 3D-printed PCL scaffolds
were integrated with dynamic vascular endothelial growth Low molecular weight gelators (LMWG) with
factor (VEGF)–DNA hydrogel and reinforced using black nucleoside/nucleotide precursors are also considered
phosphorus (BP) nanosheets (BPNSs). The scaffolds were DNA-based hydrogels. A self-assembled metallo-
nucleoside injectable hydrogel was reported for wound
used to improve bone regeneration and angiogenesis. repair. In this study, cytidine (C) along with B(OH)
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BPNSs were employed to form a dynamic polymer network, and AgNO were used as precursors, where C formed
3
ensuring sufficient mechanical strength while preserving 3 +
the protein binding surface. In addition, the interaction of orthogonal diester bonds with borate, while Ag stabilized
BPNSs further increased the storage modulus. Additional the C-C base pairs through dimers (Figure 6F). The
crosslinking further stabilized the scaffolds into a denser formed hydrogel was stable with high water content,
nano-composite. The DNA gel also facilitated long-term stimuli-responsive, self-supporting, and elastic. Its sol–gel
transition upon applied shear stress enabled a 3D-printed
retention and delivery of biologically active VEGF, thereby and flexible wound healing patch with antibacterial activity
promoting angiogenesis and osteoinductivity. A versatile induced by the incorporated Ag .
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+
supramolecular hydrogel incorporating chemically
branched DNA on self-complimentary linkers (Figure These studies demonstrate the versatile applications of
6C) and a K ion-responsive pure DNA hydrogel with DNA-based supramolecular hydrogels in 3D bioprinting,
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Volume 10 Issue 3 (2024) 19 doi: 10.36922/ijb.3223