Cellulose-Based Aggregation-Induced Emission Microspheres for Visual Detection of Nitroaromatic Explosives

The development of sustainable and portable sensors for nitroaromatic explosives detection is essential for environmental monitoring and public safety. In this work, positively charged cellulose-based fluorescent microspheres were fabricated for the visual detection of 2,4,6-trinitrophenol (PA). Cellulose microspheres with controllable diameters were prepared through the coaxial airflow method, followed by grafting the aggregation-induced emission (AIE) fluorogen tetraphenylethylene (TPE) and quaternary ammonium groups (N⁺-COOH) to yield MCC-TPE-N⁺ microspheres. These microspheres integrate AIE fluorescence, porous structure, and a positively charged surface, achieving a limit of detection (LOD) of 0.035 μM for PA, which surpasses the performance of pristine TPE-Br probes (0.36 μM). Moreover, the microspheres exhibited adequate recyclability, operational stability in aqueous environments, and visual detection capability. This work highlights the dual role of cellulose as a structural scaffold for analyte enrichment and a versatile template for AIEgen immobilization and charge modification, offering a sustainable and efficient strategy for the development of eco-friendly, high-performance fluorescent sensing platforms based on renewable polymers.