Table 3.

Hydrogel-based biomaterials for controlled drug delivery.

Type	Polymer	Drug delivered	Drug type	Mode of release	Reference
Natural hydrogels	Alginate	VEGF	Protein	Diffusive	Silva and Mooney (2007, 2010)
	Alginate	VEGF and PDGF	Dual proteins	Diffusive	Sylven et al. (2007)
	Fibrin	VEGF	Protein	Proteolytic degradation	Ehrbar et al. (2004)
	Extracellular matrix	bFGF	Protein	sGAG-binding affinity	Seif-Naraghi et al. (2012)
	Extracellular matrix	HGF-f	Protein fragment	sGAG-binding affinity	Sonnenberg et al. (2015)
	Gelatin	FGF-2 and G-CSF	Dual proteins	Diffusive and ionic interactions	Layman et al. (2009)
	Hyaluronic acid	TGF-β1	Protein	Heparin-binding affinity	Jha et al. (2015)
	Matrigel	T7 Vasculotide	PEG-peptide tetramer	Diffusive	Van Slyke et al. (2009)
	Matrigel	Qk	Peptide	Diffusive	Santulli et al. (2009)
Synthetic hydrogels	Poly(ethylene glycol) multiacrylate and dithiolthreitol	hGH	Protein	Dissolution and diffusion	van de Wetering et al. (2005)
	Poly(ethylene glycol vinyl sulfone and proteolytically cleavable peptide	VEGF	Protein	Enzymatically responsive	Zisch et al. (2003)
	Poly(ethylene glycol) diacrylate and proteolytically cleavable peptide	VEGF	Protein	Enzymatically responsive	Phelps et al. (2010)
	Poly(ethylene glycol) norbornene and enzymatically cleavable peptide	Qk, SPARC113, SPARC118, and model peptides	Peptide	Enzymatically responsive	Van Hove et al. (2014)
	Poly(N-isopropylacrylamide-co-propylacrylic acid-co-butyl acrylate)	bFGF	Protein	pH-responsive and diffusive	Garbern et al. (2010), Murry et al. (2011)
Combinatory/hybrid hydrogels	Poly(ethylene glycol)-bis-butanoic acid and hydrazide-functionalized heparin	VEGF	Protein	Heparin-binding affinity	Tae et al. (2006)
	Multi-arm poly(ethylene glycol) thiol and dextran vinyl sulfone	IgG, BSA, Lysozyme, and bFGF	Protein	Diffusive	Hiemstra et al. (2007)
	Poly(ether)urethane–polydimethylsiloxane + fibrin	VEGF and bFGF	Dual proteins	Diffusive	Losi et al. (2010)
	Hyaluronic acid + PEG	VEGF and bFGF	Protein	Heparin-binding affinity	Pike et al. (2006)

Select examples of hydrogel-based biomaterials used for controlled drug delivery.