• The acute embryotoxicity assessment of ZnO and ZnO-LMWCH nanocomposites in zebrafish embryos • The significant reduction in morphological abnormalities and cardiac toxicity following chitosan functionalization • The protective role of low molecular weight chitosan derived from Sepia brevimana in mitigating ZnO-induced developmental toxicity • The enhanced biocompatibility of ZnO-LMWCH nanocomposites for environmental and biomedical applications This study presents the first comprehensive toxicological evaluation of Sepia brevimana -derived low molecular weight chitosan (LMWCH) functionalized zinc oxide nanocomposites in zebrafish ( Danio rerio ) embryos. Uncoated ZnO and LMWCH -coated ZnO nanocomposites were assessed at concentrations of 1–8 µg/mL across 24, 48, and 72 h post-fertilization. Uncoated ZnO induced severe dose-dependent embryotoxicity, including yolk sac edema, spinal deformities, reduced body curvature, and significantly decreased cardiac function. In contrast, chitosan-coated ZnO nanocomposites demonstrated significantly ( P<0.05 ) reduced toxicity across all concentrations, with embryos exhibiting normal morphological development and heart rates comparable to controls even at 8 µg/mL. The marine biopolymer coating effectively mitigated Zn²⁺ ion leaching and oxidative stress, demonstrating superior cardioprotective and developmental safety profiles. These findings establish chitosan-coated ZnO nanocomposites as biocompatible alternatives for environmental remediation and biomedical applications, highlighting the critical role of biopolymer functionalization in enhancing nanomaterial safety while preserving photocatalytic efficiency.
Senthil et al. (Sun,) studied this question.