Page 14 - MSAM-4-2

Materials Science in Additive Manufacturing Hydrogels in mandibular reconstruction

stability need to be improved. A double-network hydrogel fluids, ensuring stable adhesion to physiological tissue
containing magnesium ions was synthesized using in situ surfaces. However, hydration barriers often hinder effective
radical polymerization and crosslinking via magnesium tissue-hydrogel integration.
ion coordination. The introduction of magnesium ions In recent years, researchers have developed novel
not only increased the crosslinking density of the hydrogel hydrogel systems integrating wet adhesion and mechanical
but also enhanced its mechanical strength and stability. reinforcement through biomimetic design and multi-scale
The hydrogel, enhanced by integrating a double-network composite strategies. Inspired by marine mussel adhesive
architecture and POSS-Mg composites, achieved a six-fold proteins, chemical modifications based on L-DOPA or
increase in peak compressive strength. This improvement catechol groups can endow hydrogels with robust wet
highlights its suitability for applications such as bone adhesion at tissue interfaces. These systems overcome
40
regeneration and promoting blood vessel formation in rat hydration barriers through covalent crosslinking between
cranial defect models. 35
catechol groups and tissue surface amino/thiol groups,
Furthermore, adjusting parameters such as hydrogel coupled with metal coordination. For example, Hu et al.
41
component concentrations or molecular weights can developed an L-DOPA-PVA-ZIF-8 hydrogel (L-DPZ) that
markedly improve mechanical properties such as elastic integrates multiple functionalities through a biomimetic
modulus and tensile strength. However, mechanical approach: a biocompatible PVA polymer matrix was
enhancement inevitably introduces challenges, including covalently grafted with L-DOPA to provide catechol
fabrication complexity, altered degradation kinetics, active groups, while ZIF-8 nanoparticles formed a metal-
and potential component toxicity. Therefore, to meet the catecholamine coordination network. This system achieved
unique demands of mandibular defect repair, current a shear strength of 10 MPa through amino/thiol covalent
research must focus on optimizing synthesis protocols, bonds and metal coordination. In addition, the high
degradation parameters, and biosafety evaluation systems porosity of ZIF-8 enabled controlled Zn release, promoting
2+
to synergistically enhance mechanical compatibility, tissue osteogenic differentiation of rat BMSCs. Simultaneously,
induction, and clinical translatability. Table 1 summarizes nano-scale bonding between ZIF-8 and catechol groups
recent advances in mechanically reinforced hydrogels for significantly enhanced mechanical strength, ensuring
mandibular defect repair. that hydrogel degradation kinetics matched new bone
regeneration. This strategy demonstrates potential for
3.1.2. Adhesion resolving clinical challenges such as stabilizing comminuted
An ideal hydrogel for maxillofacial repair must exhibit fractures, reconstructing bone defects, and replanting teeth,
strong adhesiveness to resist washing by blood and tissue offering promising solutions in complex medical scenarios.

Table 1. Applications of mechanically enhanced hydrogels for the repair of mandibular defects
Composite Cell type Animal model Outcome achieved References
hydrogels
nHA@ADA/Gel MC3T3-E1, ATCC SD rats critical-sized • Increased mechanical strength 36
mandibular defects • Antioxidant capacity
• Promoted mandibular bone regeneration
BPDAH-GPEGD BMSC, macrophage SD rat cranial defect • Excellent injectability, self‑healing property and 37
shape adaptability
• Increased mechanical strength
• Repaired critical‑sized skull bone defect
SIM@ZIF-8/ BMSC SD rats cranial and • Excellent injectability and mechanical strength 38
PEGDA/SA premaxillary defect • Promoted osteogenesis and suppress adipogenesis
POSS-UPy PDLSCs Cranial bone defect • Increased mechanical strength 21
• Promoted osteogenesis
SF/MBG/SA BMSC Rabbit maxillary sinus • Great injectability and shapeability 39
elevation • Increased mechanical strength
• Promoted osteogenesis
Abbreviations: ADA: Alginate dialdehyde; BMSC: Bone marrow stromal cell; BPDAH: BMP-2 loaded polydopamine/heparin nanoparticles;
GPEGD: Gelatin/polyethylene glycol diacrylate/2-(dimethylamino) ethyl methacrylate; MBG: Bioactive mesoporous glass; nHA: Nano-sized
hydroxyapatite; PDLSCs: Periodontal ligament stem cells; PEGDA: Polyethylene glycol diacrylate; POSS-UPy: Polyhedral oligomeric silsesquioxane
2-ureido-4[1H]-pyrimidinone; SA: Sodium alginate; SD: Sprague–Dawley; SF: Silk fibroin; SIM@ZIF-8: simvastatin-laden zeolitic imidazolate
framework-8.

Volume 4 Issue 2 (2025) 8 doi: 10.36922/MSAM025070006