The present study was conducted to evaluate the insecticidal efficiency and safety of zinc oxide nanoparticles (ZnO NPs) and hydrophilic silica nanoparticles (SiO2 NPs) against: adults of rice weevil (Sitophilus oryzae L.); red flour beetle (Tribolium castaneum Herbst.) and cowpea beetle (Callosobruchus maculatus F.) results showed that, both ZnO NPs and hydrophilic SiO2 NPs exhibited a significant toxic effect (df, F and p < 0.5) against S. oryzae and C. maculatus at the highest concentration while T. castaneum showed high resistance against the two tested materials. At the end of the experiment, recorded mortality was: 81.6, 98.3 and 58.3% at the highest concentration used for each insect (0.3, 2 and 8 gm ⋅ kg–1 of SNPs with C. maculatus, S. oryzae and T. castaneum, respectively), while mortality was 88.3, 100 and 38.3% at the highest concentration used for each insect (0.6, 2.5 and 8 gm ⋅ kg–1 of ZnO NPs with C. maculatus, S. oryzae and T. castaneum, respectively). Both tested materials caused high reductions in F1-progeny (%) with C. maculatus and S. oryzae. Histopathological examination of male mice livers showed hepatic architecture with congested blood sinusoids, binucleated hepatocytes nuclei, dilated central vein and margainated chromatin in some nuclei. Histopathological assessment of the lungs showed normal histoarchitecture. There were no differences in alveolar septa, bronchiolar and epithelium of the treated and untreated animals. Silica and zinc oxide nanoparticles have a good potential to be used as stored seed protectant alternatives if applied with proper safety precautions.

Photoactive nanofilled nematic is proposed. Stable three-component photoresponsive nanocomposite was prepared from photo-insensitive nanofilled nematic by inclusion of 3 wt.% azobenzene-containing photoactive mesogen 4-(4′-ethoxyphenylazo)phenyl hexanoate (EPH). The host nanofilled nematic was produced from the room-temperature nematic liquid crystal 4-n-heptyl cyanobiphenyl (7CB) and 3 wt.% filler of Aerosil 300 hydrophilic silica nanospheres of size 7 nm. Apparent effect of stimulation with a relatively weak continuous illumination by UV light (375 nm wavelength) takes place for both the alternating-current electric field-dependent optical transmittance and the electro-optic amplitude-frequency modulation by thin films (25 µm thick) of the EPH/aerosil/7CB nanocomposite. The light-stimulated electro-optics of EPH-doped aerosil/7CB films and the corresponding reversible light control are achieved through trans-cis-trans photoisomerization of the photoactive agent EPH. As such, the initial electro-optical response of the studied photoactive nanocomposites is recovered with continuous blue-light illumination. The examined EPH/aerosil/7CB nanocomposites exhibit photo-controllable electro-optical response that is of practical interest.