Silk fibroin‐mediated and tannic acid‐zinc functionalized CaCO3 microspheres for fipronil delivery with pH‐responsiveness and high foliar affinity

Abstract BACKGROUND The inefficient overuse of pesticides due to low foliar adhesion, can cause irreversible damage to the environment and human health. Thus, increasing foliar adhesion of pesticides has been a major challenge. Porous materials with the capacity to deliver pesticides in a responsive manner offer new opportunities to increase pesticidal efficacy and efficiency. RESULTS Here, a novel pH‐responsive fipronil (FIP)‐loaded microsphere, named FIP@SC‐TZ, was designed using calcium carbonate (CaCO 3 ) coordinated with tannic acid (TA) and zinc acetate (ZA). Silk fibroin (SF)‐mediated biomineralization was employed to prepare homogeneous and porous vaterite CaCO 3 . Results demonstrated that the SF‐mediated CaCO 3 possessed spherical morphology of 1.51 μm was obtained as the concentration of SF was 2 wt%. The pesticide loading capacity of the prepared FIP@SC‐TZ was 15.6%. Notably, the cumulative release of FIP@SC‐TZ at pH 2 was 86.2%. The contact angle of FIP@SC‐TZ on cabbage leaves was 63°, and the flush resistance of FIP@SC‐TZ was 67.7%, 1.3 times higher than that of FIP alone. Besides, FIP@SC‐TZ exhibited high insecticidal efficacy, and long release time on Spodoptera litura. CONCLUSIONS Consequently, FIP@SC‐TZ offered a new approach for pH‐responsive and foliar adhesive pesticide delivery system, facilitating the use efficiency of pesticides and showing promising potential for sustainable agriculture and clean production. © 2025 Society of Chemical Industry.