Cost-effective synthesis of zinc oxide/crab shell-derived chitosan nanocomposite: Insights into its biomedical...

For biomedical applications, material scientists all over the world are working to develop cost-effective technologies and thereby synthesize new nanocomposite materials that are biocompatible, bioactive, scalable and naturally abundant. This study focuses on synthesizing and evaluating nanocomposites of zinc oxide (ZnO) and chitosan (CS) derived from crab shells, in three different weight proportions (1:0.5, 1:1, and 1:2). ZnO/CS nanocomposites were synthesized using a soft-chemical method. Characterization of the nanocomposites was done using XRD, FESEM, EDAX, FTIR, and PL techniques. Among the three formulations, the ZnO/CS nanocomposite with a 1:2 ratio (ZnO/CS)_1:2 exhibited the most significant antioxidant, anti-diabetic, and antibacterial properties. The (ZnO/CS)_1:2 demonstrated 89.46 and 90.85 % of inhibition in DPPH and superoxide free radical scavenging assays, respectively, and showed 91.86 % inhibition against the alpha-glucosidase enzyme. It also exhibited strong antibacterial activity against both gram-positive (Staphylococcus epidermidis, Bacillus subtilis) and gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Additionally, the cytotoxicity of the (ZnO/CS)_1:2 nanocomposite was assessed against the MCF-7 breast cancer cell line, showing an IC₅₀ value of 11.58 ± 0.05 μg/mL at 30 μg/mL. The (ZnO/CS)_1:2 nanocomposite shows potential as a candidate for biomedical applications, particularly in antioxidant, anti-diabetic, and antibacterial activities.