Fluorescence Correlation Spectroscopy (FCS) Unlocks the Presence of Microcystin-LR in Fresh Water

Water is essential for human life, and access to clean water is considered a basic human right by the United Nations. Around the world, a high proportion of the population still does not have access to safe fresh water, with a high impact on health. This situation perpetuates a cycle of poverty, hindering economic development and exacerbating inequality. The water is considered unsafe to drink if it is contaminated. The contamination can be categorized into three types: physical, chemical, and biological. Biological contamination arises from the presence of living organisms in water, such as bacteria, viruses, algae, fungi, and parasites. Recently, the scientific community has raised the alarm on contamination caused by a large group of bacteria known as Cyanobacteria, which can release harmful toxins in water, including mycotoxins like Microcystin-LR (MC-LR). In this context, we present the application of fluorescence correlation spectroscopy (FCS) to develop a competitive assay for detecting the presence of traces of the MC-LR toxin in fresh water.