“Safe” Chitosan Zinc Oxide Nanocomposite Has Minimal Organ-Specific Toxicity on Early Stages of Zebrafish Development

Abstract

Marine biofouling is considered one of the most challenging issues affecting maritime industries worldwide. In this regard, traditional biocides, being used to combat biofouling, have high toxicity toward the aquatic system. Recently, a new chitosan/zinc oxide nanoparticle (CZNCs) composite has been used as promising “green” biocides. It is thought that due to the eco-friendly nature of chitosan, our newly synthesized CZNCs may pave the way to develop less toxic surfaces for combating marine fouling. Zebrafish has become one of the most employed models for ecotoxicology studies. Therefore, this study aims to comprehensively evaluate any potential acute, cardio, neuro, or hepatotoxic effect of CZNCs using zebrafish embryos. As evidenced by the acute toxicity assays, exposure of zebrafish embryos to CZNCs (25-200 mg/L) failed to elicit any signs of acute toxicity or mortality, suggesting a hypothetical LC50 higher than the maximum dose employed. CZNCs, at a concentration of 250 mg/L also showed no cardiotoxic or neurotoxic effects. At the same dosage, a minor hepatotoxic effect was observed in zebrafish embryos exposed to CZNCs. However, the observed hepatotoxicity had no effect on embryos survival even after long-term (10-days) exposure to CZNCs. We believe our results add valuable information to the potential toxicity of chitosan-metal oxide nanoparticle-based hybrid nanocomposites, which may provide new insights for the synthesis of ecofriendly coatings with improved antifouling performance and a low adverse impact on marine environment.