Toxicological investigations of biosynthesized nickel ferrites nanoparticles on midgut epithelium of Blaps polychresta as nanopesticides: Structural damages and oxidative stress

Abstract

The development of eco-friendly insecticides with the ability to overcome insecticide resistance remains a thorny issue. This study therefore intends to evaluate the effectiveness of green synthesized nickel ferrite nanoparticles (NiFe₂O₄ NPs) as nanopesticides in this first report using darkling beetles, Blaps polychresta, as a model. The biosynthesized NiFe₂O₄ NPs were characterized employing various approaches, including FTIR, UV–Vis spectroscopy, XRD, XPS, and VSM. The morphological features and size of the nanoparticles were determined adopting SEM and TEM analyses, revealing that NiFe₂O₄ NPs have an average size of 24.59 nm with a quasi-spherical shape. The beetles treated with NiFe₂O₄ NPs showed their accumulation in midgut tissues, as evidenced by EDX analysis. Accumulation of NiFe₂O₄ NPs in midgut epithelium induced surplus reactive oxygen species (ROS) production, engendering elevated MDA level linked with increased expression of MT1 and HSP70. Besides, decreased GST, SOD, and GSH activities were also reported. These findings indicate antioxidant defense systems malfunction due to failure of NiFe₂O₄ NPs detoxification. Beyond that, comet assay and flow cytometry analysis exhibited noticeable amplifications of DNA impairment and cellular apoptosis, respectively, in beetles treated with NiFe₂O₄ NPs compared to untreated beetles. Pathohistological and ultrastructure investigations showed various aberrations in beetles exposed to NiFe₂O₄ NPs, including rapture of midgut epithelium and necrotic signs, substantiating the biochemical findings. These findings suggest that NiFe₂O₄ NPs could be implemented in agricultural practices as a sustainable insecticidal candidate to manage insect pests. Further studies are required to investigate NiFe₂O₄ NPs interaction with environmental conditions.