Table 2.

List of patents surveyed for gradient scaffolds

Patent Number	Author	Gradient	Intended Application
Application US20060121609 A1 (2006)	Yannas et al. (44)	Pore diameter, chemical composition, crosslink density	Soft tissue-bone interface
Application US20050118236 A1 (2005)	Qiu et al. (45)	Porosity, fiber/mesh density	Osteochondral interface
Issued, US 6306424 B1, US 6306424 B1 (2006)	Vyakarnam et al. (43)	Porosity of lyophilized foams	Osteochondral interface
Issued, US7524513 B2 (2009)	Hai-Quan et al. (46)	Covalently bonded biofunctional ligands and growth factors	Vascular –smooth muscle interface
Application US20070212730 A1 US20130230491 A1 (2013)	Vepari et al. (47)	Covalently bonded proteins and enzymes	Bone-ligament interface
Issued, US 8277832 B2 (2014)	Detamore et al. (48)	Physical properties of microspheres	Osteochondral interface
Issued, US 8986380 B2 (2015)	Kaplan et al. (49)	Multilayered silk scaffold with pore gradient	Meniscus tissue
Issued, US7767221 B2 (2010)	Lu et al. (50)	Physical properties of microspheres incorporated into a composite scaffold	Soft tissue-bone interface