A Pectin-Responsive Aggregation-Induced Emission Probe for Specific Staining of Plant Cell Walls

Efficient visualization of the plant cell wall is fundamental to advancing plant science. This study presents an innovative utilization of an aggregation-induced emission (AIE)-active iridium complex in specific plant cell imaging. Complex Ir-Am with two amine groups exhibited selective and efficient phosphorescence response to pectin, a major structural component of plant cell walls. Mechanism investigations confirmed that the binding between pectin and Ir-Am is mediated by amine-carboxylic interactions, which in turn fixed the conformation of Ir-Am for activating its AIE. Imaging experiments further demonstrated that Ir-Am can successfully label the plant cell wall in different tissues of the model plants and exhibit outstanding staining performance compared to conventional dyes such as Congo red and propidium iodide. This research not only presents an effective and innovative approach for visualizing the plant cell walls but also greatly broadens the applications of iridium complexes as powerful tools for botanical studies.