Seed-Inspired Sandwich-Structured Nanofibers Enable Intelligent Delivery of Prothioconazole

Prothioconazole (PTC), a broad-spectrum fungicide, shows limited persistence and a short residual activity. Inspired by the seed’s protective dormancy and conditional germination mechanism, we fabricated a bionic sandwich-structured nanofiber (EC-PTC/GEL-EC NF) via sequential electrospinning. The ethyl cellulose (EC) outer layer mimics the seed coat for slow release, while the gelatin (GEL) inner layer acts as the responsive embryo, enabling pH/temperature dual-responsive release. The EC-PTC/GEL-EC NF achieved a cumulative release exceeding 85% and extended the functional duration beyond 96 h. The release is driven by the GEL network, which opens or closes release channels in response to stimuli, working in concert with the EC matrix, which adjusts its permeability to synergistically control diffusion. Structurally, the resulting EC-PTC/GEL-EC NF effectively encapsulates PTC and exhibits a smooth morphology free of granules. Additionally, antifungal testing against Rhizoctonia solani revealed that the EC-PTC/GEL-EC NF exhibited significantly enhanced bioactivity, with a 21.13% higher inhibition rate than free PTC on day 4. The LC50 value of EC-PTC/GEL-EC NF is 2.38 times greater than that of PTC, indicating reduced ecotoxicological risk to nontarget soil organism earthworms.