Table 2.

Overview on relevant publications using chondroitin sulfate (CS)- and heparin (HE)-based cryogels.

GAG	Further (Co)Polymer	Crosslinking	Properties	Applications	References
CS	HA/Gel	EDC	Open connected pore morphology (diameter: 100–350 µm)	Cartilage tissue engineering	[35]
	HA/Gel/Chitosan		Chitosan incorporation increases elastic modulus (stiffness) and toughness; pore diameter: 100–500 µm; cultivation of chondrocytes from rabbit knee articular cartilage Dynamic cultivation of porcine chondrocytes and adipose-derived stem cells under cyclic loading		[36]
CS	HA/Gel/Chitosan/PVA	Glutar dialdehyde	Unidirectional freeze-drying (pore size: 10–210 µm vertical and 20–160 µm transverse section, respectively), porosity 93–98%	Tracheal scaffold fabrication	[37]
CS-methacrylate	Gel-methacrylate	Free radical polymerization (APS/TEMED)	Inter-connected macroporous structure; pore diameters about 89 µm; compressive modulus about 38 kPa; supports chondrocyte phenotype and cellular distribution; subcutaneous implantation of cell-laden cryogel in mice led to dense deposition of cartilage-specific ECM molecules	Cartilage tissue engineering	[38]
CS-methacrylate	PEG-diacrylate	Free radical polymerization (APS/TEMED)	Formation of penetrating polymer network (IPN); ChS-based cryogel showed elevated elastic modulus compared to HA-based system; pore diameter of about 63 µm	Cartilage tissue engineering	[39]
HE	4arm-PEG-NH2	EDC/Sulfo-NHS	Macroporous, interconnective 3D-architecture, pore size ranges between 10 and 80 μm; cryogels behave mechanically comparable to the native ECM of soft tissue, showing locally a high resistance to mechanical stress but low bulk stiffness	Endothelial cell cultivation	[40]
				Carrier for pancreative islets	[41]
				Cancer immunotherapy	[42]
				Cytokine release to the brain	[43]
			stem cell culture; RGD-modification-mediated cell adhesion	Neural cell cultivation	[44,45]
HE	Gel	EDC/Sulfo-NHS	Microporous, interconnective architecture stable against enzymatic degradation; injectable	Neovascularization; cell carrier	[46]
	Gel/Whitlockite		stem cell differentiation	Bone tissue engineering	[47,48]
HE	Chitosan; PVA; Hydroxyapatite (HA)	Glutar dialdehyde	Large continuous interconnected pores, slowly degradable network, with 10% HA mechanically stable for bone implantation	Scaffold for growth factor (e.g., BMP-2) delivery	[49]
HE-methacrylate	Alginate-methacrylate; PEG-acrylate-RGD	APS/TEMED	Interconnected porous structure, increase in shape recovery of coated hybrid grafts, enabling cell adherence and growth	Cryogel coating of prosthetic grafts	[50]

PVA: Poly(vinyl alcohol): PEG: Poly(ethylene glycol); Sulfo-NHS: N-hydroxysulfosuccinimide; RGD: Trimeric cell attachment sequence (Arg-Gly-Asp).