*2.9. Biocompatibility Evaluation*

The acute systemic toxicity assay was usually selected to measure the adverse effect of biomedical materials that result either from a single exposure or from multiple exposures in a short period of time. It is an important indicator of biosafety assessment [72]. To evaluate the biosafety of aquatic collagen, porcine collagen was designated as a comparison group. As shown in Figure 6, no significant difference in body weight was observed between the experimental groups and the control group at four hours, 24 h, 48 h, and 72 h after the intraperitoneal injection of the collagen leach liquor. Moreover, the weight of the control group and the experimental groups increased significantly over time, and no dead samples appeared. Furthermore, there were no significant differences between the ASC, PSC, and PC groups. The results showed that ASC and PSC collagen sponges were produced by our process without acute systemic toxicity, and there was not a significant difference from the acute toxicity from commercially available porcine collagen products.

**Figure 6.** Weight changes of mice after intraperitoneal injection. The different letters in the same group (same type of the bar) represent significant difference (*p* < 0.05).
