Zein-functionalized mesoporous silica as nanocarriers for nanopesticides with pH/enzyme dual responsive properties

Excessive use of non-renewable surfactants, low utilization efficiency, and uncontrollable release behavior are the urgent disadvantages in traditional pesticide formulations. In this work, zein was used to modify mesoporous silica as nanocarriers to load avermectin to obtain the nanopesticides. Due to the unique properties of zein, the nanopesticides were responsive to pH and enzyme. The pesticide release at alkaline condition was controlled by the electrostatic repulsion between zein and pesticide, while the controlled release of pesticide in the presence of enzyme was due to the cleavage of peptide bond in zein, and the relevant release mechanisms were also elucidated. Besides, these nanopesticides exhibited a high pesticide loading capacity above 280 mg g−1, and such nanocarriers reduced the degradation rate of the pesticide against ultraviolet irradiation about 55%. Also, these nanopesticides demonstrated enhanced wetting and adhesion properties on cucumber foliar surfaces, and they show comparable pesticidal efficacy with the pure pesticide. Therefore, this work provides a facile and environmentally friendly strategy to prepare a dual responsive nanopesticide system, and the controlled release performance, high pesticide loading capacity, enhanced photostability, remarkable pesticidal efficacy, and improved wetting and adhesion properties of the resultant nanopesticides make them potential for agricultural applications.