Advances in Science
The nano-fibrous structure was attributed to the noncovalent assembly mechanism, resembling other self-assembly macromolecular hydrogel system structures. The degradation properties of HA-LMWH/PEG-HIP hydrogel were monitored in PBS at 37oC as a function of incubation time. The HA-LMWH solution, and the other HIP mediated hydrogel without flexible PEG chains, e. g. HA-LMWH/HIP, were also investigated as control groups. As shown in Figure 3a, HA-LMWH/HIP was dismissed in 2 days, while HA-LMWH/PEG-HIP hydrogel lost its weight steadily up to 14 days. At day 14, the weight remaining ratio of the HALMWH/PEG-HIP hydrogel was 62%. Since swelling properties of hydrogel scaffolds are crucial for substance exchange during ASCs differentiation, the swelling kinetics of the HA-LMWH, HA-LMWH/HIP, and HA-LMWH/PEGHIP were investigated in PBS (Figure 3b). The results showed that both of the HA-LMWH and HA-LMWH/HIP dismissed in 2 days, which was consistent with the data of weight loss shown in Figure 3a. The swelling ratio of the HALMWH/PEG-HIP hydrogel significantly increased from 31.2 to 40.4 when incubated for 14 days. These results clearly demonstrated that the HIP alone was unable to interlink the HA-LMWH, while the PEG-HIP can serve as an elastic cross-link in noncovalently assembled nano-fibrous hydrogel networks, which was accessible for conjugating with LMWH in aqueous environment.
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Figure 3. (a) Degradation of hydrogels in PBS at 37째C with respect to weight loss. (b) Swelling kinetics of hydrogels in PBS as a function of incubation time.
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