TABLE 1.

Functional hydrogels for skin wound healing.

Hydrogels	Bond chemistry of hydrogels	Structure of hydrogels	Functionalization of hydrogels	Animal models	References
Gelatin/poly (vinyl alcohol) hydrogels	Dynamic phenylboronic acid−diol-ester bonds	Injectable hydrogel	Vancomycin-conjugated silver nanoclusters, pH-sensitive micelles loaded with Nimesulide	Diabetic rat model	Wang et al. (2021b)
Heparin-poloxamer hydrogels	Amido bond	Patch	Different growth factor (a-FGF and b-FGF)	Rat full-thickness skin defect model	Wu et al. (2016)
Bacterial cellulose/MXene hydrogels	Hydrogen bond, chemical covalent cross-linking bond, chain self-entanglement	Patch	Ti3C2Tx-MXene	Rat full-thickness skin defect model	Mao et al. (2020)
Calcium peroxide-GelMA hydrogels	Carbon-carbon covalent bonds	3D printed patch	Calcium peroxide	—	Erdem et al. (2020)
Bilayered thiolated alginate/polyethylene glycol diacrylate hydrogels	Disulfide bond, Carbon-carbon covalent bonds	Bilayered patch	The small extracellular vesicles (sEVs) secreted by bone marrow derived mesenchymal stem cells, and the sEVs secreted by miR-29b-3p-enriched bone marrow derived mesenchymal stem cells	Full-thickness skin defect model of rats and rabbit ears	Shen et al. (2021)
VEGF-decorated t-ZnO-laden hydrogels	Carbon-carbon covalent bonds	3D printed patch	Tetrapodal zinc oxide, VEGF	Full-thickness skin defect model	Siebert et al. (2021)
Poly (lactic-co-glycolic acid) microcapsules hydrogels	Imine crosslinking	Injectable hydrogel	TGF-β inhibitor	Rabbit ear and porcine skin wounding model	Zhang et al. (2021a)
Bio-multifunctional hydrogels	MgO-catechol, Schiff’s base bond	Injectable hydrogel	MgO	Full-thickness cutaneous defect and burn model	Tang et al. (2021)
Multifunctional double colorimetry-integrated polyacrylamide-quaternary ammonium chitosan-carbon quantum dots-phenol red hydrogels	Carbon-carbon covalent bonds, physical entanglement	Patch	Carbon quantum dots, phenol red	Rat skin defect model	Zheng et al. (2021)
The peptide modified nanofibers reinforced hydrogels	Schiff’s base bond	Composite hydrogel	Antimicrobial peptide (RRRFRADA)	Murine diabetic wound healing model	Qiu et al. (2021)
Sodium alginate-chitosan oligosaccharide-zinc oxide hydrogels	Schiff’s base bond	Patch	Zinc oxide nanoparticles	Second-degree scald wounds model	Zhang et al. (2021b)
Catechol/ε-polylysine hydrogels	Schiff’s base bond	Patch	Catechol, ε-polylysine	Burn Wound Infection Model	Xu et al. (2019b)
Polypeptide-based FHE hydrogels	Schiff’s base bond	Injectable and self-healing	stimuli-responsive adipose-derived mesenchymal stem cells exosomes	Diabetic rat model	Wang et al. (2019a)
Metallohydrogels	Coordination self-assembly	Patch	Amino acid, Ag+	Bacterial infection rat model	Song et al. (2020)
Hydrogel/polycaprolactone core/shell fiber scaffolds	Ionic bond	3D printed patch	Polydopamine, doxorubicin	Rat full-thickness skin defect model	Liu et al. (2021)
Gelatin-Tannic acid hydrogels	Hydrogen Bond	Patch	Tannic acid, allantion	Rat full-thickness skin defect model	Ahmadian et al. (2021)
Epigallocatechin-3-gallate-3-acrylamido phenylboronic acid complex-based polyacrylamide hydrogels	Boronate ester bond, phenylboronate ester	Patch	Epigallocatechin-3-gallate, 3-acrylamido phenylboronic acid	The diabetic rat model	Zhao et al. (2021b)
Injectable multifunctional hydrogels	Schiff’s base bond	Injectable hydrogel	ε-polylysine-coated MnO2 nanosheets, insulin	The diabetic rat model	Wang et al. (2020)
Polydopamine-modified graphene oxide hydrogels	Schiff’s base bond	Patch	Graphene oxide, ε-polylysine	The diabetic rat model	Tu et al. (2021)
Sprayable hydrogels	Carbon-carbon covalent bonds	sprayable	Cerium oxide nanoparticles, antimicrobial peptide	Infected rat model	Cheng et al. (2021)
Dual-dynamic-bond cross-linked antibacterial adhesive hydrogels	pH-sensitive coordinate bond, Schiff’s base bond	Patch	Protocatechualdehyde, ferric iron	Rat skin incision model	Liang et al. (2021)
Polyvinyl alcohol-iodine hydrogels	Hydrogen bond	Patch	Iodine	Rat skin incision model	Miao et al. (2021)
Cellulose-based adhesive hydrogels	Covalent bond, hydrogen bond, cation-π, π-π stacking, electrostatic interaction	Patch	—	Rat full-thickness skin defect model	Lu et al. (2021)