Enzyme Immobilization by Hydrogen-Bonded Organic Framework for the Construction of Plant-Wearable Sensor

It is of great significance to on-site detection of pesticides for food safety and pollution monitoring. Plant-wearable sensors (PWS) are capable of real-time detection of pesticides on crops, which facilitates the precise application of pesticides and determines whether the plant-based foods meet the criteria for safe consumption. Herein, PWS are designed by embedding an acetylcholinesterase@poly(allylamine hydrochloride)-hydrogen-bonded organic frameworks (AChE@PAH-HOF) in hydrogel discs to on-site deliver pesticide-residue information. The self-assembly of AChE@PAH-HOF, achieved via electronic interactions and hydrogen bonding with a crystalline structure-directing agent, exhibits high catalytic activity and enhances stability. To facilitate long-term and precision monitoring of organophosphorus pesticides, a PWS is constructed by integrating the AChE@PAH-HOF into a glycerol-sodium alginate hydrogel matrix, which provides high water-retaining capacity essential for sustained operation under high-temperature. By integrating with the image processing algorithm, the PWS successfully achieves in situ monitoring of pesticide degradation on tomato plants, demonstrating superior accuracy and sensitivity to chlorpyrifos with a detection limit of 1 ng mL^-1. Such a PWS enables non-invasive, cost-effective pesticide detection in agricultural settings, supporting targeted crop health management and sustainable precision farming practices.