Dual-Modal Fluorometric and Colorimetric Label-Free Pyrrole-Functionalized Semiconducting Polymer Dots for Highly Efficient 2,4,6-Trinitrotoluene Detection in Environmental Samples and Cellular Imaging Publisher



Moghadam MZ ; Shamsipur M ; Alipour M ; Yousefi V ; Hajipourverdom B ; Moodi M ; Hosseinkhani S ; Hosseni M ; Mehrafza M ; Molaabasi F
Source: Microchemical Journal Published:2026

Abstract

An efficient selective detection of the trace trinitrotoluene (TNT) explosive by a simple, green, inexpensive, and fast method is challenging. Owing to its high oxidation ability and explosive power, TNT is required against terrorism, while causing harm to the environment, and human health. In the present work, a new effective on-off probe was developed for the selective and sensitive detection of TNT within 3 min based on utilizing highly fluorescent pyrrole-factionalized-PFBT polymer dots (Pdots). The developed sensing platform was easily prepared in one step during less than an hour by only doping a monomer into the target polymers. This strategy not only overcomes the limitation of time-consuming multi-step and multi-reagent synthesis, but also maintains the superior fluorescence property, and biocompatibility of PFBT. The developed Pdots with a diameter of 30 nm revealed a strong green fluorescence centered at 530 nm (λex = 470 nm). The designed PFBT sensor revealed an excellent selectivity in alkaline media, so that the fluorescence of the as-prepared Pdots significantly quenched in the presence of TNT over other structurally similar nitroaromatics (NACs). This could be attributed to two simultaneously occurring mechanisms: inner filter effect (IFE) and aggregation-caused quenching (ACQ). Molecular ducking was also successfully used to analyze binding energy (ΔG) and dissociation constant (Kd). Moreover, interestingly, this innovative and simply designed sensor was applied to colorimetric assay via Meisenheimer complex formation at alkaline media. A good linear relationship was obtained from 4.0 nM to 60.0 μM for on-off fluorescence detection of TNT with an excellent detection limit of 2.2 nM and 0–158 μM with the detection limit of 0.20 μM for off-on colorimetric assay. The developed dual-modal pyrrole-PFBT probe could be applied in different environmental river water, tap water, well water, and soil samples. Finally, the designed pyrrole-PFBT probe revealed the high potential in cellular imaging with the best photostability. © 2025 Elsevier B.V.