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Materials Science in Additive Manufacturing Hydrogels in mandibular reconstruction

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Figure 5. Multifunctional ADA-Gel/nHA composite hydrogels demonstrate moldable architectures, robust mechanical behavior, and flexibility suitable for
biomedical bone regeneration applications. (A) Schematic diagram of chemical and ionic crosslinking (Ca ) of a composite ADA-Gel hydrogel modified
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with nHA, where dynamically dissociated PO and Ca interact with biopolymers to form tight and compact structures. Created with BioRender.com.
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(B) Adaptability of composite hydrogels in molds with different shapes. (C) Flexibility of composite hydrogels adhered on knuckles. (D) Compressive
stress-strain curves of composite hydrogels. (E) Tensile stress-strain curves of composite hydrogels. Panels B-E reprinted with permission from ref.
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Copyright © 2022 Elsevier
Abbreviations: ADA: Alginate dialdehyde; nHA: Nano-sized hydroxyapatite
mechanical properties after instantaneous curing but also dual network and enzymatic mineralization in enhancing
exhibited robust gel stability in simulated physiological mechanical properties: Young’s modulus reached 1.03 MPa
environments (moisture and bleeding). It induced H-type (20408% higher than pure PVA), storage modulus 103
angiogenesis, activated Osterix + osteoprogenitor cells, kPa (697% higher), and equilibrium swelling ratio 132%
and created an anti-inflammatory microenvironment, (47% higher). Notably, the mineralized PVA-SA hydrogel
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achieving successful mandibular regeneration in an retained high toughness (1.86 MJ/m ) and demonstrated
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MRONJ rat model. osteogenic potential. Li et al. designed a biomimetic DN
composite hydrogel (GelMA/DNA/Apt19S/AptV, GDSV)
Dual-network (DN) hydrogels, formed by mimicking the bone ECM. By integrating a covalent GelMA
interpenetrating and independently crosslinked natural or network with an aptamer-functionalized DNA physical
synthetic polymers, combine the advantageous properties of network, the hydrogel achieved hierarchical regulation
both components. Compared to traditional single-network of vascularized bone regeneration. The GelMA network
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hydrogels, DN hydrogels significantly enhance strength and provided mechanical and biological stability, while the DNA
toughness through an interpenetrating network of rigid network enabled dynamic capabilities like stress relaxation.
polyelectrolytes and flexible neutral polymers, utilizing Functionalized aptamers (Apt19S and AptV) mediated
a “sacrificial bond” mechanism for stress dispersion. bone marrow stromal cell (BMSC) recruitment and VEGF-
This makes them more suitable for maxillofacial tissue controlled release, establishing a dual bio-regulatory
engineering under high mechanical loads. Zhang et al. mechanism in a cell-free scaffold: The DNA network’s
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developed a DN hydrogel using polyvinyl alcohol (PVA) dynamic mechanical microenvironment synergized with
and sodium alginate (SA) through freeze-thaw cycling and GelMA’s rigid support and time-dependent VEGF release
ionic crosslinking, followed by enzymatic mineralization. to accelerate bone repair. Traditional GelMA exhibits
The results revealed synergistic effects between the PVA-SA good biocompatibility, but its mechanical strength and

Volume 4 Issue 2 (2025) 7 doi: 10.36922/MSAM025070006