Poly(Styrene Sulfonate)/Poly(Allylamine Hydrochloride) Encapsulation of TiO 2 Nanoparticles Boosts Their Toxic and Repellent Activity Against Zika Virus Mosquito Vectors

Abstract

Green fabricated nanoparticles often need to be encapsulated and stabilized, to ensure uniform dispersion in the aquatic environment and relevant larvicidal activity over time. However, recent research showed that nanoencapsulation processes led to a reduction of nanoparticle larvicidal efficacy. We used an extract of Argemone mexicana to reduce TiO₂ nanoparticles, which were then capped with PSS/PAH (poly(styrene sulfonate)/poly(allylamine hydrochloride)). The toxic and repellent potential of the nanoparticles were compared to elucidate their potential effects against the Zika virus vector Aedes aegypti. Nanoparticles were characterized by biophysical methods including UV–Vis, EDX and FTIR spectroscopy, SEM, TEM, XRD and DLS analyses. In larvicidal and pupicidal experiments, TiO₂ nanoparticles achieved LC₉₀ values from 41.648 (larva I), to 71.74 ppm (pupa). Nanoencapsulated TiO₂ achieved LC₉₀ values from 39.16 (I), to 69.12 ppm (pupa). In adulticidal experiments, LC₉₀ of TiO₂ nanoparticles on Ae. aegypti was 10.31 ppm, while LC₉₀ of nanoencapsulated TiO₂ was 9.54 ppm. At 10 ppm, the repellency towards Ae. aegypti was 80.43% for TiO₂ nanoparticles, and 88.04% for nanoencapsulated TiO₂. This research firstly highlighted the promising potential of PSS/PAH encapsulation, leading to the production of highly effective titania nanostructures, if compared to titania nanoparticles synthesized with eco-friendly routes without further stabilization.