Supramolecular methods: the 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) transport assay

The vesicular anion transport activity assay, which uses 8-hydroxypyrene-1,3,6-trisulfonic acid to monitor the internal pH of the vesicles (the HPTS assay), is a widely used technique for analysing the activity of anionophore facilitated transport across a phospholipid membrane. This methods paper describes the stepwise technique to conduct this transport assay, detailing both the perks and pitfalls of using this method to determine the activity of an anionophore and the transport mechanism.