Improving the Efficiency and Environmental Safety of Emamectin Benzoate through a pH-Responsive Metal–Organic Framework Microencapsulation Strategy

Herein, we developed a technique for loading nanopesticides onto Metal-Organic Frameworks (MOFs) to control Spodoptera litura. The average short-axis length of the synthesized carrier emamectin benzoate@PCN-222@hyaluronic acid (EB@PCN-222@HA) was ~40 nm, with an average long-axis length of ~80 nm. This enabled the manipulation of its size, contact angle, and surface tension on the surface of leaves. Pesticide-loading capacity, determined via thermogravimetric analysis, was measured at ~16%. To ensure accurate pesticide release in the alkaline intestine of Spodoptera litura, EB@PCN-222@HA was engineered to decompose under alkaline conditions. In addition, the carrier delayed the degradation rate of EB, enhancing EB's stability. Loading Nile red onto PCN-222@HA revealed potential entry into the insect body through feeding, which was supported by bioassay experiments. Results demonstrated the sustained-release performance of EB@PCN-222@HA, extending its effective duration. The impact of different carrier concentrations on root length, stem length, fresh weight, and germination rate of pakchoi and tomato were assessed. Promisingly, the carrier exhibited a growth-promoting effect on the fresh weight of both the crops. Furthermore, cytotoxicity experiments confirmed its safety for humans. In cytotoxicity assays, PCN-222@HA showed minimal toxicity at concentrations up to 100 mg/L, with cell survival rates above 80%. Notably, the EB@PCN-222@HA complex demonstrated reduced cytotoxicity compared to EB alone, supporting its safety for human applications. This study presents a safe and effective approach for pest control using controlled-release pesticides with extended effective durations. This study aims to enhance the efficiency and environmental safety of Emamectin Benzoate (EB) through a pH-responsive Metal-Organic Frameworks (MOFs) microencapsulation strategy for controlling Spodoptera litura. The synthesized EB@PCN-222@HA nanoparticles showed controlled release under alkaline conditions, extending efficacy. Bioassay results indicated sustained pest control. Assessment on plant growth and cytotoxicity revealed environmental safety. This work presents a safe and effective approach for pest control, extending pesticide duration.