Introduction

Weeds seriously affect crop yield in global agricultural production. Paraquat (PQ), as one of low cost and highly effective herbicide, is forbidden or severely restricted in production and sales owing to its lethal toxicity to humans. Creating an efficient and bio-friendly PQ formulation is crucial to facilitate the open use of PQ in world’s agriculture.

Objectives

This study aims to construct one intelligent and bio-friendly mesoporous carbon nanoparticles (MCN) nanoherbicides coated with α-CD polymer (CDP) gatekeepers.

Methods

MCN was prepared through the low-concentration hydrothermal way, calcined and carbonized. PEG stalks were immobilized on MCN surface by amidation reaction. The PQ was trapped in the MCN pores via physical diffusion adsorption and the robust π–π effects between electron-deficient PQ and electron-rich MCN. CDP gatekeepers were fastened via host–guest effects between the chamber of α-CD units and PEG stalks.

Results

The PQ-loaded MCN-PEG@CDP nanoherbicides integrated with multi-stimuli responses to amylase, elevated temperature under sunlight, and competitors at leaf interface to control the PQ release for efficient weed control, while appeared low PQ leakage under the simulated human gastric or intestinal conditions, low cytotoxicity to human normal cells in vitro, and high mouse survival rate in vivo. Even through the nanoherbicides inevitably contact with water or intake by beneficial insects, they appear good biosafety on zebrafish (D. rerio) and honeybees (Apis mellifera L.).

Conclusion

The as-prepared nanoherbicides have high herbicidal efficacy and low risks to non-target species, and could promote the open use of PQ in agriculture.

中文翻译：

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生物友好型多刺激响应 α-CD 聚合物门控介孔碳纳米除草剂，可增强百草枯的递送

 介绍

杂草严重影响全球农业生产中的作物产量。百草枯 （PQ） 作为一种低成本、高效的除草剂，由于其对人体的致命毒性而被禁止或严格限制生产和销售。创造高效且生物友好的 PQ 配方对于促进 PQ 在世界农业中的公开使用至关重要。

 目标

本研究旨在构建一种涂有 α-CD 聚合物 （CDP） 守门人的智能且生物友好的介孔碳纳米颗粒 （MCN） 纳米除草剂。

 方法

采用低浓度水热法制备MCN，经煅烧、碳化处理。通过酰胺化反应将 PEG 茎固定在 MCN 表面。PQ 通过物理扩散吸附以及缺电子 PQ 和富电子 MCN 之间的稳健π-π效应被捕获在 MCN 孔中。CDP 守门人通过 α-CD 单元腔室和 PEG 茎之间的主客体效应固定。

 结果

负载 PQ 的 MCN-PEG@CDP 纳米除草剂结合对淀粉酶的多重刺激反应、阳光下的高温和叶片界面的竞争物，以控制 PQ 释放以实现有效的杂草控制，同时在模拟人胃或肠道条件下出现低 PQ 泄漏，体外对人正常细胞的细胞毒性低，小鼠体内存活率高.即使纳米除草剂不可避免地与水接触或被益虫摄入，它们对斑马鱼 （D. rerio） 和蜜蜂 （Apis mellifera L.） 似乎具有良好的生物安全性。

 结论

所制备的纳米除草剂除草效果高，对非目标物种的风险低，可促进 PQ 在农业中的公开使用。