Table 8.

Miscellaneous synthetic and composite hydrogels in neural regeneration.

Hydrogel Structure	Hydrogel Physical, Chemical, and Biological Characteristics	Neural Disease/Disorder Targeted	Ref
Pure silk fibroin hydrogel with aligned microgrooved structure	High mechanical strength, biocompatibility; supports aligned Schwann cell growth	Peripheral nerve regeneration	[34]
Ammonia-functionalized graphene oxide and frankincense-embedded hydrogel	Synergistic effect on axon regrowth; increases regenerating axons and myelin thickness	Facial nerve regeneration	[82]
Polyacrylamide/chitosan composite hydrogel	Elasticity and topographical guidance; promotes dorsal root ganglion neurite growth and better-oriented status	Peripheral nerve regeneration	[83]
Collagen/terpolymer hydrogel-filament scaffolds	Enhanced neurite extension, directional growth along fibers, higher levels of Na channels	Peripheral nerve regeneration	[84]
Polyacrylonitrile (PAN) conduit with fibrin hydrogel and graphene quantum dots (GQDs)	Promotes Schwann cell infiltration, improves sensorial recovery, enhances axon numbers and remyelination	Sciatic nerve injury	[85]
Photo-patterned hydrogels with microchannels (fibrin, PEG/fibrinogen, gelatin)	Provides contact guidance, controlled environmental stimuli, uniform tissue propagation, unidirectional growth	Sciatic nerve injury	[86]
Poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (PHEMA-MMA) hydrogel	Supports nerve regeneration comparable to autografts, promotes axonal regeneration	Sciatic nerve injury	[87]
GelMA/PEtOx hydrogel with 4-Aminopyridine (4-AP)	High porosity, sustainable drug release, good blood compatibility, enhances neuromuscular function	Sciatic nerve injury	[88]
Biofunctionalized anisotropic PAM hydrogel with YIGSR peptide	Adhesive; directionally induces cell alignment, accelerates cell migration, upregulates BDNF and beta-actin expression	Peripheral nerve regeneration	[89]
Poly-N-isopropylacrylamide (PNIPAM) hydrogel with dopamine-modified MWCNTs	Photothermal responsiveness, porous, good hydrophilicity; supports Schwann cell growth and nerve growth factor release	Peripheral nerve injury	[90]
Polyamidoamine (PAA) hydrogel	Biocompatible, biodegradable, tunable elasticity; facilitates nerve regeneration, with no inflammation or neuroma	Sciatic nerve injury	[91]
Polyacrylamide/silk fibroin/graphene oxide composite hydrogel	Excellent 3D network structure, hydrophilicity, wettability, and porosity, enhanced mechanical strength; supports Schwann cell growth	Peripheral nerve regeneration	[92]
Bisphosphonate-based injectable hydrogel with magnesium (Mg)	Sustained Mg2+ delivery; promotes neurite outgrowth via PI3K/Akt pathway, enhances axon regeneration and remyelination	Peripheral nerve injury	[93]
Macrophage-polarizing in situ visible-light-crosslinkable adhesive protein hydrogel containing functional neurotransmitter peptide	In situ crosslinking, macrophage polarization, effective tissue remodeling, sutureless anastomosis	Peripheral nerve injury (PNI)	[94]
Three-dimensional hierarchically aligned fibrin nanofiber hydrogel	Hierarchically aligned topography, low elasticity; mimics nerve ECM, promotes rapid directional cell adhesion	Peripheral nerve injury (PNI)	[95]
Graphene foam/hydrogel-based scaffold loaded with adipose-derived stem cells	Excellent mechanical strength, suitable porous network, superior electrical conductivity, good biocompatibility	Diabetic peripheral nerve injury (DPNI)	[96]
Graphene mesh-supported double-network (DN) hydrogel scaffold using natural hydrogel conduit (alginate and gelatin-methacryloyl) loaded with netrin-1	Good flexibility, Young’s modulus of 725.8 ± 46.52 kPa, electrical conductivity of 6.8 ± 0.85 S/m, UV crosslinking, biocompatible	Peripheral nerve injury	[97]
Poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (PHEMA-MMA) coil-reinforced hydrogel tubes	Patency, structural reinforcement, comparable mechanical properties to autografts	Peripheral nerve injury	[98]
Gelatin methacryloyl (GelMA) hydrogel	Photocrosslinkable, 10% (w/v), initiated under blue light (405 nm), good mechanical properties	Spinal cord injury	[99]
3D-printed polymeric hydrogels	Customizable structures, improved nerve reparation through bioprinting	Nerve cell regeneration	[100]