Assessment of multifunctional activity of graphene oxide and guar gum-based nanomaterials against Aedes aegypti.

Nanomaterials have been receiving much research attention in controlling insect pests and vectors. Properties, such as small surface-to-volume ratio, low dosages, durability, solubility, enhanced target activity, pore size and surface characteristics have enabled the design of precise and targeted insecticides through adsorption, encapsulation, and conjugation. The reported study aims to evaluate the efficacy of graphene oxide (GO) and guar gum (GG)-based nanomaterials against early fourth instar of Aedes aegypti, a mosquito responsible for transmitting diseases like dengue fever, Zika, and chikungunya, among many others. GO and a total of eight nanomaterials (SA-1 to SA-8) were formulated using GO, GG and their combinations with ferrous oxide and copper oxide. Each material was characterized using various biophysical techniques. The materials were evaluated for larvicidal potential by assessing their efficacy on the survival and morphology of Ae. aegypti, while the contact irritancy activity focused on determining their irritant properties upon direct exposure to the female adults. The larvicidal and irritant bioassays, conducted with these nanomaterials at different concentrations, demonstrated concentration-dependent mortality and significant behavioral responses. The exposures with nanomaterials also resulted in a deposition of black soot on the larval cuticle. The most effective nanomaterial was found as ferrous oxide nanomaterial which induced 100% larval mortality as well as significant contact irritancy. The results indicate the potential use of GO and GG-based nanomaterials against Ae. aegypti after concentration optimization.