Although we have produced evidence that supports the hypothesis that SSAs are able to act as selective phospholipid membrane coordination and/or disruption agents, to date we have minimal evidence that verifies the role ion transport events may play in the SSA mechanism of biological activity, or the types of transmembrane SSA structures which may be involved in facilitating these events, such as ion channels or membrane pores. Therefore, to confirm the role ion transport may play in the biological activity of SSAs, we also explored the ability of SSAs 1, 3, 5, 7 and 9 to mediate ion transport in phospholipid vesicles (Section S17 † ). We initially performed a Cl -/NO3 -antiport assay. In this assay, large unilamellar vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were prepared containing NaCl (ionic strength = 500 mM) buffered to pH 7.2 with sodium phosphate salts. The vesicles were suspended in NaNO3 (ionic strength = 500 mM) at pH 7.2 (Figure ). On addition of the SSA as a 5 mM DMSO stock solution (which was maintained throughout these experiments to minimise any variation in aggregation state induced by changes in concentration), any resulting chloride efflux was detected using a chloride ion selective electrode (ISE). We observed that all of these molecules excluding compound 1 (Section S17 † ) mediated a modest amount of chloride efflux when added at 10 mol% w.r.t. lipid (Figure ). This observation is surprising given the negative charge of the SSA anion. Comparable experiments in which the external anion was replaced with SO4 2-resulted in greatly reduced chloride efflux, indicating a likely anion antiport mechanism. Introducing a pH gradient into the Cl -/ SO4 2-vesicle system also did not result in improved chloride efflux, indicating that an HCl co-transport mechanism is unlikely to be occurring to a significant degree in these experiments. We were unable to observe significant transport activity when these compounds were added as a stock solution dissolved in water (5 mM). Hill plot analyses were used to quantify the efficacy of Cl -/NO3 -antiport, generating comparable values of EC50 (the concentration of transporter required to mediate 50% chloride efflux after 270 s -Section S17 † ). The reciprocal of the EC50 values are summarised in Figure , to visualise a comparison of the overall efficacies, with the most active compounds exhibiting the largest 1/EC50 values. From these data, we observe that 3, 5, 7 and 9 are modest anion antiporters (EC50 > 15 mol% w.r.t. lipid in each case). SSA 9 was the most active transporter within this series, and we observed two major trends: (i) in each case, the SSAs containing unnatural D-amino acids (5 and 9) are more active than their L-counterparts (3 and 5); (ii) the transport efficacy of the 1:1 enantiomeric mixture were significantly reduced compared to the most active enantiomer of each pair. We speculate that this reduced activity could result from differences in self-associative processes adopted by the SSA enantiomeric mixtures when compared to the homogenous aggregates produced by a single SSA as evidenced by Q 1 H NMR spectroscopy experiment (Table