High-Porosity Hydrogel Microneedles for Rapid and Efficient Extraction of Imidacloprid Residues in Peach Fruits

Accurate and rapid extraction of pesticide residues in fruits is crucial for timely food safety monitoring. However, conventional extraction methods remain labor-intensive and time-consuming, often requiring hours for sample preparation. Here, we present a porous hydrogel microneedle (HMN) patch integrated with an automated insertion applicator as a highly efficient platform for the rapid extraction of peach juice for imidacloprid residue detection. The HMN patch, composed of polymethyl vinyl ether/maleic anhydride (PMVE/MA) polymer, was fabricated with high porosity by adjusting the porogen content. Under optimized porogen content of 3% NaHCO₃, the developed HMN patch exhibited ultrahigh extraction efficiency, achieving a 40-fold water absorption capacity and extracting 0.6% (w/w) peach solids of its weight within 5 min. The extracted juice could be readily recovered through a simple elution process and was directly compatible with both high-performance liquid chromatography (HPLC) analysis and lateral flow assays. Compared with conventional destructive methods, the HMN platform offers a scalable, high-efficiency, and user-friendly solution for high-throughput pesticide extraction. The integration of the automated applicator further enhances consistency, minimizes user variability, and facilitates on-site monitoring of pesticide residues, providing a practical pathway for field-deployable food safety monitoring.