Carboxymethyl cellulose-coated iron-doped hollow silica carriers with erythrocyte-like structure for improved foliar adhesion and responsive pesticide delivery.

The development of nanopestcide carriers with high foliage adhesion remains a challenging task. Erythrocytes are double concave disc structure with thinner center and thicker rim and erythrocyte-like carriers would present enhanced foliar affinity. In this study, we fabricated novel rough-surfaced erythrocyte-like carriers for pesticide delivery. Firstly, erythrocyte-like silica (ES) nanoparticles were prepared by sol-gel method. Subsequently, the ES nanoparticles were further hydrothermal treated to obtain rough-surfaced iron-doped hollow ES (Fe-EHS) nanocarriers. The Fe-EHS nanocarriers could increase contact area and form a topological effect between the pesticide carriers and the micro/nanostructures on plant foliage, effectively enhancing the retention and rain fastness on foliage. Fe-EHS nanocarriers presented a loading capacity of 38.1 % for imidacloprid (IMI). After loading IMI, carboxymethyl cellulose (CMC) was encapsulated to generate nanopesticide delivery system (IMI@Fe-EHS-CMC). The obtained IMI@Fe-EHS-CMC exhibited good foliar adhesion, biosafety, and excellent UV shielding. Additionally, the IMI@Fe-EHS-CMC system possessed pH/cellulase responsive release behavior and could be bidirectionally transported through vascular bundles in tobacco plants. Furthermore, the IMI@Fe-EHS-CMC system showed potent insecticidal activity. This work offers valuable insights for enhancing the effective utilization of pesticides.