A critical review on smart fluorescent platforms for mercury detection: Mechanistic insights, supramolecular systems and real-world applications

Fluorescent sensors have emerged as a promising alternative to traditional systematic methods for identifying mercury (Hg 2+ ) contamination, a foremost global concern due to its significant toxicity and persistence in biological and environmental systems. This review examines various fluorescent sensing platforms developed between 2016 and 2025, including molecular probes, aggregation-induced emission (AIE) systems, aptamer/nanomaterial hybrids, supramolecular assemblies, metal-organic frameworks (MOFs), Schiff-base derivatives, and polymer-based sensors, while highlighting design strategies and key photophysical process such as fluorescence resonance energy transfer (FRET), internal charge transfer,CHEF /CHEQ, photoinduced electron transfer (PET), also AIE, along with performance metrics like detection limits, selectivity, and response times, and also exploring solid-state and device-oriented formats such as paper strips, cryogels, MOF films, organogels, and smartphone-utilising platforms, while emphasizing the probes' testing with real samples from environmental fluids, food matrices, soils, and biological systems, and providing a comprehensive assessment of limitations, including regeneration challenges, short-term stability issues, interference from complex matrices, and solvent dependency, ultimately culminating in a roadmap for developing fully aqueous, low-toxicity, reusable solutions.