Zeolitic imidazolate framework-encapsulated zinc porphyrin photoresponsive nanozyme for colorimetric/fluorescent dual-mode sensing of glyphosate

Abstract

A novel zeolitic imidazolate framework-encapsulated zinc porphyrin (ZnTCPP@ZIF-90) photoresponsive nanozyme is proposed for the colorimetric/fluorescent dual-mode visual sensing of glyphosate (Gly). ZnTCPP@ZIF-90 exhibits photoresponsive oxidase-like activity and fluorescence quenching behavior. Meanwhile, the outer ZIF-90 layer can be selectively destroyed by Gly, causing the release of free ZnTCPP, resulting in the enhanced enzyme-like activity as well as fluorescence emission. The constructed ZnTCPP@ZIF-90 was successfully used for the colorimetric/fluorescent dual-mode detection of Gly. Additionally, the colorimetric and fluorescent images information captured by the smartphone were converted to color intensity (HSV/RGB values), with limits of detection of 0.27 μg/mL and 0.19 μg/mL, respectively. The proposed dual-mode sensor exhibits excellent selectivity and reliability for detecting Gly, and can be successfully applied to the analysis of real samples such as tap water, lake water, and fruit washing water. The current research efforts are expected to provide new perspectives for designing highly active photoresponsive nanozymes and their stimuli-responsive sensing systems, paving the way for their applications in portable dual-mode chemical sensing and environmental monitoring.