Metal Extrusion Assays as a Tool for Sulfate Recognition

Abstract

Sulfate is a biologically relevant anion found in an array of aqueous media including biological and environmental fluids, including blood plasma and seawater. While sulfate is highly prevalent in these media, selective detection of sulfate poses a challenge due to its similarities with other relevant anions. While receptors specifically designed for sulfate have often been used, assay based approaches can also be used for sulfate recognition. In this study, Metal Extrusion Assays (MEAs) are used as a new approach for sulfate recognition. While this approach has been used for recognition of other relevant anions, this study presents one of the first MEAs for sulfate in a range of aqueous media. To determine if this approach can be used for sulfate recognition in aqueous complex media, a range of synthetic and analytical techniques were employed, with fluorescence and UV-vis spectroscopy used as the main tools to detect binding. The photophysical characteristics of a range of receptors was determined in conjunction with studying these receptors as tools for cation binding. This then informed the creation of the MEAs, which were employed to detect sulfate. Variation of the receptor-ligand combination allowed for sulfate detection through MEAs in biological fluid mimics and seawater mimics, indicating the potential of MEAs for use in complex media.