Fabrication of zein-coated brush-like silica nanocarriers for high foliage deposition and responsive release of pesticide.

ABSTRACT

Responsive release systems have received extensive attention to enhance pesticide utilization efficiency and reduce environmental pollution. In this study, pH/GSH dual responsive release system based on brush-like silica (bSiO2) carriers was constructed to enhance the utilization of pesticides. The bSiO2 carriers present core-shell structure, length of 550 nm, diameter of 350 nm and shell thickness of 100 nm. The carrier had a high pesticide loading (20.0 %, w/w) for dinotefuran (Din). After loading Din, zein was covalently linked with cysteine-bridge to seal the loaded pesticides (namely Din@bSiO2@Zein). The Din@bSiO2@Zein exhibited superior foliar affinity, retention and photostability, and retention rate still remain above 95 % with 220 min UV irradiation. Din@bSiO2@Zein displayed pH/GSH responsive release and the cumulative release within 92 h was up to 81 % under pH=9/CGSH=6 mM, mimicking the microenvironment of lepidopteran. The Din@bSiO2@Zein possessed good control efficacy against Plutella xylostella. Appreciably, Din@bSiO2@Zein could be transported bi-directionally to various regions of tobacco plants within 24 h, which had potential to promote pesticide efficacy. This work offers a strategy to minimize the pesticide dosage and encourage sustainable agricultural development.