Table 2.

Examples of injectable hydrogels for cartilage tissue engineering

Gelation	Mechanism	Polymer	Cells	References
Physical crosslinking	Ionic	alginate-graft-hyaluronate	Chondrocytes (mouse)	226
	pH-sensitive	poly(γ-glutamic acid)-PEG	cartilage chondrocytes (bovine)	227
	Thermo-sensitive	Pluronics®; methylcellulose; PNIPAAm-gelatin	Chondrocytes (goat); articular chondrocytes (rabbit); chondrocytes (rabbit)	228-230
Chemical crosslinking	Michael addition	thiolated hyaluronic acid and PEG vinylsulfone; dextran-PEG	Chondrocytes; chondrocytes or embryonic stem cells	108, 112
	Click chemistry	dextran-based hydrogels; HA/PEG hydrogel	Chondrocytes (rabbit); Chondrocytes (mouse)	106, 142
	Enzyme-catalyzed	glycopolypeptides	Chondrocytes	231
	Schiff-base reaction	N-succinyl-chitosan (S-CS) and aldehyde hyaluronic acid (A-HA); poly(ethylene oxide-co-glycidol)-CHO and glycol chitosan (GC)	articular chondrocytes (bovine); chondrocyte (mouse)	71, 232
	Photo-polymerization	methacrylated hyaluronan, methacrylated gelatin	MSCs (humam); hBMSCs	165, 233, 234

HA, Hyaluronic acid; ACM, acellular cartilage matrix; BMHP, bone marrow homing peptide; SAP, self-assembling peptide; PEG, poly (ethylene glycol); PNIPAAm, poly(N-isopropyl acrylamide).