Marine-derived phosphorylated chitosan: Structural insights and bioactivities of a novel carbohydrate polymer.

Phosphorylation of chitosan derived from Loligo duvauceli offers a promising strategy to enhance its biomedical functionality. This research investigates the therapeutic potential of phosphorylated chitosan (PCH) synthesized from the gladius (internal shell) of L. duvauceli, with a focus on its antibacterial, antioxidant, and anticoagulant properties. Structural and morphological modifications following phosphorylation were confirmed through Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) analyses. Antibacterial evaluation revealed effective inhibition against both Gram-positive bacteria (Staphylococcus aureus, 12 ± 1.25 mm) and Gram-negative bacteria (Escherichia coli, 10 ± 0.82 mm). Antioxidant activity was assessed via DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, superoxide radical scavenging assay, and ferrous ion chelation assay. These tests demonstrated robust free radical neutralization. Anticoagulant efficacy was validated through activated partial thromboplastin time (APTT: 111 ± 3.52 s at 100 μg/mL) and prothrombin time (PT: 72 ± 2.25 s at 100 μg/mL). Results indicate significant prolongation of clotting times and modulation of the intrinsic coagulation pathway. These findings confirm the multifunctional bioactivity of PCH and underscore its promise as an eco-friendly biopolymer derived from marine organisms for innovative biomedical applications.