ENZYMATICALLY TRIGGERED IN SITU GEL-FORMING BIOMATERIALS FOR REGENERATIVE MEDICINE - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 115

Table 6.1. Substrates, gelation times, and mechanical strengths of major
enzyme-triggered hydrogels.

Gelation Mechanical

Enzyme Substrate time strength Reference

∼ − − ,

000 Pa b HRP (HA)-TA 10 400s 850 3 Kurisawa et al.

Calabro et al.

∼ − . − .

5N a Chitosan-PA 5 400s 0 5 2 Feijen et al.

∼ − >

10 3 Pa b Chitosan-GA/PA 10 250s Sakai et al.

Dextran-TA ∼ 10 − 250s ∼ 10 4 Pa b Feijen et al.

Gelatin-TA ∼ 5 − 150s 0.07 − 0.2 N a Sakai et al.

Alginate-TA ∼ 10 − 250s 0.01 − 0.1 N/mm 2 c Sakai et al.

Carboxymethyl- ∼ 5 − 500s N.A. Sakai et al.

cellulose-TA
Tetronic-TA 200 − 10 4 Pa b ∼ 2 − 120s Park et al.

500 − 10 4 Pa b HA (or gelatin)- ∼ 5 − 60s Park et al.

TA /Tetronic-TA
Tetronic-RGD/TA 500 − 10 4 Pa b ∼ 2 − 180s Park et al.

TGase PEG-peptides 15 − 50 min N.A. Gri th et al. Messersmith et al.

soy protein isolate 20 − 250 min 10 − 400 Pa b Zhang et al.

∼ 10 2 Pa b gelatin 2 − 3hr Kobayashi et al. Payne et al.

∼ 200 − 3000Pa b fibrinogen < 1hr Hubbell et al. Lutolf et al.

600Pa b Phosphatase Fmoc-peptides 3-30 min ∼ 20 − Xu et al. Ulijn et al.

200-4000 Pa b oligopeptides 2-30 min Xu et al.

a Repulsion forceby compression.
b Storage modulus.
c Stress by strain.
Abbreviations : HRP, horseradish peroxidase; HA, hyaluronic acid; TGase, transglutaminase; TA,
tyramine; RGD, Arg-Gly-Asp; PA, 3-(p-hydroxyphenyl)propionic acid; GA, glycolic acid; Fmoc, N -
(fluorenylmethyloxy-carbonyl);N.A., not available.

icalstrength,werecharacterized. 22 Manytypesofenzymeshavethe
potential for chemical cross-linking and polymerization. Table 6.1
liststhe major enzyme-triggered hydrogels formed in situ .

6.3.1 HRP-Catalyzed Systems
Peroxidase catalysis is an oxidation of a donor to an oxidized
donorthroughtheactionofhydrogenperoxide,liberatingtwowater
molecules. 23 Several studies have focused on an interesting enzyme
of peroxidase species. Horseradish peroxidase (HRP) is a single-
chain

α

-type hemoprotein that catalyzes the decomposition of