Fluorescent Chemosensor for Pyrophosphate <i>via</i> Aggregation-Induced Emission and Principal Component\nAnalysis

The fluorescent chemosensor <b>TPE-NH</b><sub><b>3</b></sub>, a derivative of tetraphenylethylene\n(TPE), substituted with\nfour cationic ammonium groups, was developed for the selective detection\nof pyrophosphate (PPi) anion. With inherent aggregation-induced emission\n(AIE) characteristics, <b>TPE-NH</b><sub><b>3</b></sub> displays strong fluorescence enhancement accompanied by a blue shift\nupon interacting with PPi. The probe exhibits good selectivity toward\nPPi over ten other anions that were tested. The interactions between <b>TPE-NH</b><sub><b>3</b></sub> and PPi were investigated\nusing Job plot analysis and molecular dynamics simulations. Dynamic\nlight scattering measurements demonstrated a 4.5-fold increase in\nparticle size of the aggregates after the addition of PPi. The morphology\nof these aggregates has been investigated using transmission electron\nmicroscopy and confocal fluorescence lifetime imaging microscopy analyses.\nPrincipal component analysis (PCA) was applied to quantify the PPi\nconcentration in unknown samples, giving good accuracy and precision\nwith a relatively low limit of detection (77 nM) and respectable error\nmargins (0.06–8.96%). This combined AIE-based sensing and PCA\napproach provides a robust, sensitive method for selective PPi detection\nwith significant potential for biomedical and environmental applications.