Biomass-derived cellulose nanoparticles display considerable neurotoxicity in zebrafish

Area of Science:

• Environmental Science
• Toxicology
• Nanotechnology

Background:

• Nanomaterials, including cellulose nanoparticles (CNs), are widely used but their environmental and developmental toxicity is not fully understood.
• Cellulose nanoparticles (CNs) derived from biomass are increasingly prevalent.
• The embryonic toxicity of CNs remains largely undetermined.

Purpose of the Study:

• To evaluate the toxicity of cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs) on zebrafish embryos.
• To investigate the effects of CNs on zebrafish embryonic development and larval motor function.
• To elucidate the underlying mechanisms of CN toxicity in the nervous system.

Main Methods:

• Zebrafish embryos were exposed to varying concentrations of CNFs and CNCs.
• FITC-coupled CNCs were used for imaging analysis to track CN accumulation in embryos.
• Zebrafish larval motor ability, motor neuron differentiation, and morphogenesis were assessed.
• Transcriptome sequencing was performed to analyze gene expression changes.

Main Results:

• No dose-dependent increase in malformation or mortality was observed in zebrafish embryos exposed to CNFs or CNCs below 30 mg/ml.
• CNs were found to accumulate significantly within zebrafish embryos.
• Exposure to CNFs or CNCs led to impaired motor function in zebrafish larvae.
• Motor neuron differentiation and morphogenesis were significantly disrupted, while vascular development remained normal.
• Transcriptome analysis indicated altered expression of neural genes, suggesting a specific neurotoxic effect.

Conclusions:

• Cellulose nanoparticles (CNFs and CNCs) do not cause significant malformation or mortality in zebrafish embryos at tested concentrations.
• CNs exhibit specific neurotoxicity in zebrafish larvae, impacting motor neuron development and function.
• The neurotoxicity of CNs is potentially mediated by alterations in neural gene expression.