Environmental contamination by intense insecticide usage is consistently proposed as a significant contributor to major hazards; further, disturbing non-target populations provoke a grave concern worldwide as they play essential roles in ecosystems. Pyriproxyfen is one of the most widely used pesticides; however, due to its probable toxicity, its global application in large amounts may result in water concentrations that exceed regulatory pollution thresholds. Herein, we describe nanopyriproxyfen-loaded sago beads (PPX-NCB) designed for the slow release of pyriproxyfen (PPX). Our design is inspired by the composite structure of sago beads, composed of several small beads resembling a pomegranate. The microscopic beads accumulate chitosan-PPX-nanomicelles cross-linked with tripolyphosphate via physical absorption, offering adequate room for water absorption and subsequent PPX release. PPX-NCB had distinct effects on the immature egg and larva of Anopheles stephensi, limiting embryonic development in the eggs while enhancing bioactivity. It affects the integument of larvae and alters the surface hydrocarbons of eggs and larvae. In addition, PPX-NCB demonstrates an improved safety profile in non-target Daphnia magna.
Keywords: cuticle hydrocarbons; eggs; mosquito; nanomicelle; pyriproxyfen; sago starch.