Table 6.2.

The effects of matrix stiffening on angiogenesis in three-dimensional in vitro models

Matrix	Method of altering matrix stiffness	Stiffness (kPa)	Angiogenic response	References
Collagen	Non-enzymatic glycation with ribose	~0.18–0.50	Increasing matrix stiffness resulted in increased angiogenic outgrowth and branching density	[12]
Collagen	Non-enzymatic glycation with glucose-6-phosphate	–	Decreased sprouting, but increased branching and tortuosity in crosslinked gels	[81]
Collagen	Transglutaminase	0.45–0.89	Increasing matrix stiffness resulted in increased angiogenic sprouting, invasion, and remodeling	[82]
Collagen	Varying oligomer: monomer ratio	~0.06–0.26	Increasing stiffness increased network length, branching, and vascularized area	[83]
Collagen	EDC/NHS	–	Increased crosslinking resulted in increased capillary number and spoke-like vessel structure	[84]
Collagen	Varying pH of polymerization solution	~5–20	Thicker, deeper capillary networks on more rigid three-dimensional collagen gels. Formation of large lumen on rigid gels compared to flexible gels	[85]