Ingestion and insecticidal effects of cetylpyridinium chloride functionalized carbon nanotubes on Spodoptera litura: oxidative stress, metabolic disruptions, and reproductive toxicity

This study investigates the insecticidal potential of cetylpyridinium chloride-functionalized carbon nanotubes (CPC-CNTs) against Spodoptera litura larvae, with a focus on oxidative stress induction, antioxidant enzyme dynamics, and reproductive toxicity. Structural analyses confirmed successful CPC functionalization of carbon nanotubes, enhancing their dispersion and biological interaction. Upon exposure, CPC-CNTs elicited dose-dependent oxidative stress, as evidenced by elevated lipid peroxidation levels (malondialdehyde reaching 6.74 ± 0.21 nmol mg⁻¹ protein) and transient increases in antioxidant enzymes. Superoxide dismutase (SOD) and catalase (CAT) peaked at 48 hours (3.58 ± 0.19 and 5.14 ± 0.17 U mg⁻¹ protein, respectively), while glutathione S-transferase (GST) also showed an initial rise followed by significant declines in all enzymes at higher concentrations and longer exposure durations, indicating compromised antioxidant defenses. Biologically, treated larvae exhibited marked feeding inhibition, developmental delays, and paralysis. Reproductive performance was significantly impaired, with fecundity decreasing by 23.7%, egg hatchability dropping from 97.3% to 76.8%, and adult emergence reduced by 35.7%. Larval mortality increased dose-dependently, reaching 42.2% at 0.6% CPC-CNTs, and malformation incidence was recorded at 23.34% in the highest treatment group. These findings reveal that CPC-CNTs exert multifaceted toxic effects on S. litura and demonstrate their promise as a nano-enabled insecticidal agent. However, further ecotoxicological assessments are essential to ensure their safe application within integrated pest management (IPM) frameworks.