Table 2.

SF hydrogels with various crosslinking strategies.

Crosslinking method	Materials	Crosslinking agent	Properties	Reference
Enzyme	SF/gelatin	Transglutaminase	Enhanced mechanical properties	[70]
Enzyme	SF/mHA	Laccase	Improved pore structure and swelling behavior Modulus= 204 kPa Fracture energy= 56.6 kJ/m3	[71]
Enzyme	SF/HA	Horseradish peroxide	High elasticity Storage moduli= 0.55 ± 0.03 kPa	[72]
Physical	SF/MA	UV Irradiation	Structural stability G′ is larger than G″	[73]
Physical	SF	Gamma irradiation	Improved gelation	[74]
Physcial	SF	Sonication	Controlled gelation	[75]
Physical	SF/gelatin	Electrostatic blending	Tailored biodegradation	[76]
Chemical	SF	Glutaraldehyde	Stiffness G′ and G″ increased by 10-fold	[77]
Chemical	SF/gelatin	Genipin	Improved mechanical properties	[78]
Chemical	SF/PVA	Dialdehyde starch	Enhanced swelling ratio	[79]
Chemical	SF/collagen/ chitosan	Glyoxal	Improved porosity Young’s modulus 73.1 ± 3.4 kPa	[80]
Chemical	SF/chitosan	EDC/NHS	Enhanced compressive strength and porous architecture G′ increased with respect to SF concentration.	[81]