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. Author manuscript; available in PMC: 2017 Feb 21.
Published in final edited form as: Soft Matter. 2016 Jan 11;12(7):2076–2085. doi: 10.1039/c5sm02668g

Figure 4. Comparison of PEG-VS and PEG-A.

Figure 4

(A) Swelling ratio, (B) the rate constant of gel formation, storage modulus after 15min of gelation (C) and after 60min (D) were compared between 5% 4-arm PEG and 8-arm PEG hydrogels (PEG-VS and PEG-A) modified with 0, 1.25, and 3mM L-Cys. For swelling ratio, there was no statistical difference between PEG-VS and PEG-A at all conditions. However, PEG-4A gels could form with a maximum of 1.25mM when PEG-4VS supported efficient network crosslinking up to 3mM modification. The rate constant of gel formation of both PEG-8VS and PEG-8A was significantly higher than those of PEG-4VS and PEG-4A at all L-Cys concentration. G’ of both unmodified 8-arm PEGs after 15min and 60min was significantly higher from G’ of both unmodified 4-arm PEGs; however, upon addition of L-Cys, there were no significant differences between G’ of PEG-8A and both 4-arm PEGs. An 'X' denotes conditions that did not form gels. All data is reported as mean ± S.D. (A) n = 8, (B – D) n = 3. Significance was determined by a two-way ANOVA followed by Bonferroni post-tests. A single asterisk (*) denoted significance among groups of PEG-VS and PEG-A (both 4 and 8-arm) modified with a same L-Cys concentration. Different lower (4-arms) and uppercase (8-arms) letter represented statistically significant difference within modified PEG-VS and PEG-A groups (both 4 and 8-arm) (p < 0.05).