pH/temperature dual-responsive antifungal delivery system based on polydopamine-modified montmorillonite for sustained essential oil release

Amid the push for sustainable agriculture, developing eco-friendly and efficient bio-agricultural solutions is essential for strengthening ecological protection and decreasing reliance on chemical pesticides. This study developed a pH/temperature dual-responsive nano-sustained-release antifungal system (OEO/PDA-MMT) based on polydopamine (PDA)-modified montmorillonite (MMT) for the encapsulation of oregano essential oil (OEO). This system exhibited multifunctional responsiveness in release behavior and synergistic photothermal enhancement. Specifically, PDA modification not only extended the essential oil release period to 360 h and imparted dual pH−/temperature-responsive characteristics but also enhanced the photothermal conversion efficiency of the material, enabling rapid heating from 20.2 °C to 50.2 °C within 10 min under 808 nm near-infrared irradiation, thereby effectively promoting the release and antifungal activity of OEO. In terms of antifungal performance, the plate assays revealed that the half-maximal effective concentration (EC 50 ) and minimum inhibitory concentration (MIC) values of OEO/PDA-MMT were reduced by over 50% and 30%, respectively, compared with free OEO. In vitro experiments against Astragalus root rot further demonstrated superior control efficacy in the prevention group, showing a 97.88% reduction in lesion area at the two times the MIC (2MIC) concentration. In summary, by constructing a nanocarrier system that integrates sustained release, environmental responsiveness, and photothermal enhancement, this study established a long-acting antifungal system with sustained-release performance, providing a novel smart-material strategy for sustainable agricultural disease management.