Table 4.

Neural tissue engineering studies using elastin-like polypeptide hydrogels.

Guest Residue(s) a)	Conjugated Molecule(s) b)	Supplement	LCST [˚C]	Modulus [kPa] f)	Experiment(s)	Significant finding(s)
K12I48	RGD, adp, and upa motifs	-	31 – 33	46 – 63	PC12 culture	Hydrogel degradability, modulus, and cell adhesivity can be tuned independently of each other Hydrogel can enhance cell proliferation and neurite extension[165]
V120, V8A64G56	-	-	29, 78	-	Rat model	Aggregated ELP improves perineural half-life and reduces systemic circulation[173]
K12I48	RGD and adp motifs	-	33	0.5 – 2.1	DRG culture	Hydrogel properties can be tuned to alter rate, length, and density of neurite outgrowth[49]
V16I48E16	-	Curcumin chemical conjugation	29	-	Toxicity assay Rat model	Released curcumin attenuates TNF⍺ toxicity Injected depot sustains curcumin release and reduces systemic circulation[174]
K12I48	RGD and adp motifs	NGF	33	0.5	DRG culture	There is a tradeoff between the chemotactic response and adhesivity of nerites[166]
K12I48 c) + HAd)	RGD and adp motifs	-	26	1	MSC culture	HA-ELP hydrogel protects cells during injection[71]
K12I48	RGD and adp motifs	-	33	0.5 – 50	NPC culture	Hydrogel degradability is responsible for NPC stemness Degradation permits cell-cell contact which affects cell maintenance[167]
K12I48	RGD and adp motifs	BMP-4 or FGF2 in media	33	0.5 – 1.5	NPC culture	Hydrogel degradability enhances neuronal and astrocytic differentiation potential[168]
M10V30 e)	-	IKVAV motif	30	1.5	Neuronal culture Mouse model	Ligand-conjugated hydrogel enhances neurite extension Hydrogel elicits no inflammatory response and facilitates angiogenesis and innervation in vivo[170]
M4I8V8	IKVAV motif	-	23	0.9 – 1.6	Neuronal culture Mouse model	Ligand-integrated hydrogel enhances neurite extension Hydrogel elicits no inflammatory response[157]
K12I48	RGD and upa motifs	-	24 – 27	1.2	OPC culture	Presence of upa motif improved OPC maturation[169]

^a)Subscripts indicate the number of pentapeptide repeats containing the respective amino acid

^b)adp – ADAM9 protease degradable sequence; upa – urokinase plasminogen activator degradable sequence

^c)hydrazine modified

^d)aldehyde modified

^e)alkene modified

^f)storage (elastic) modulus.