Eco-friendly preparation, physicochemical characterization, and cytotoxicity assessment of chitosan from Parapenaeus longirostris for biomedical applications

Exploiting shrimp waste to produce value-added biomaterials brings both environmental and biomedical benefits. In the present work, we propose to extract chitin and to produce chitosan from Parapenaeus longirostris using eco-friendly process . Chitosan was prepared using optimized steps and characterized by FTIR, 1 H NMR, XRD, SEM, EDX, and viscometry. As a preliminary screening step to assess its biocompatibility, different forms of chitosan were cultured with a unicellular strain of paramecia ( Paramecium caudatum ) and other unicellular microorganisms. The results show that chitosan obtained via the Broussignac method, using an autoclave process, exhibits a low degree of acetylation (DA = 9.1%, determined by ¹H NMR), a high molecular weight (222 kDa), a crystallinity of 49.14%, and improved solubility in 0.1% acetic acid. Furthermore, cytotoxicity evaluations demonstrated that shrimp-derived chitosan exhibited higher biocompatibility than commercial chitosan, with an approximately 15% lower mortality rate. It also promoted a significant increase in Paramecium cell density (33%), indicating a stimulatory effect on growth. In contrast, acetic acid showed a strong cytotoxic effect on the culture, inducing a mortality rate of about 80%.Overall, the results are promising and suggest that naturally derived chitosan has strong potential as a non-toxic and sustainable biomaterial, while this simple and ethical unicellular model provides a preliminary, first-line screening platform, to be confirmed through further biological validation prior to in vivo studies in animal models.