Nanomaterial-based fluorescent biosensors for monitoring environmental pollutants: A critical review

The growing interest in nanomaterials with advanced optoelectronic properties has promoted the advancement of biosensors with various applications. In the environmental field, the need for rapid detection of pollutants in water sources has opened the door to fluorescent biosensors. These systems are quite sensitive and simple. Nanomaterials such as carbon dots (CD), quantum dots (QD), gold nanoparticles, nanoclusters, graphene (G), graphene oxide (GO), transition metal dialcogens (TMDC) and organometallic frameworks (MOF), have been used in the development of fluorescent detection systems. They are usually based on the Förster resonance energy transfer (FRET) quenching principle. Nanomaterials can be bioconjugated with molecules such as antibodies, enzymes or aptamers, to achieve specific detection of the target pollutant, even in real samples. This review conducts a critical analysis of the operating principle of different nanomaterial-based fluorescent biosensors. We discuss the detection of substances of high concern like heavy metals, pesticides, and so-called emerging contaminants. The advantages and disadvantages of the methods are discussed, as well as recommendations for future approaches and a possible massification of these systems.