2.5.5 Degradation study
The degradation behavior of the control SA/Gel and A-SA-Gel hydrogel samples was examined by immersing them in SBF at pH 7.4 at 37 °C, simulating the degradation condition by hydrolysis. In this study, the samples were weighed (dry mass Mo ) and placed into a petri dish with PBS (pH 7.4) and RPMI 1640 culture medium, separately. The samples were incubated at 37 °C for up to 5 days, and PBS and culture medium were replaced every day. After the predetermined time intervals, the samples were wrapped with lint-free filter paper to remove excess PBS or culture medium from the surface of the samples and then kept into a drying oven at 37 °C to dry. The final mass of dry samples was recorded (Mt ). The percentage of weight loss was calculated according to the following formula:
Weight loss (%) = [|Mt – Mo|/ Mo ] × 100%
The morphology of the SA/Gel and A-SA-Gel hydrogel samples were also examined by using SEM (HITACHI SU-1510, Japan) after degradation of 1, 3 and 5 days.