After observing K + transport by SSA 1, we next sought to investigate the deliverability of this transporter. As summarised previously, synthetic ionophores are commonly highly lipophilic structures, which can result in poor water solubility and thus poor deliverability, limiting prospects for medicinal applications. Many synthetic transporters in the literature are tested in vesicle assays as stock solutions in organic solvents such as DMSO or ethanol, and previous work has established that the nature and quantity of the solvent can affect the delivery of the transporter to the lipid bilayer and hence the observed activity. In contrast, SSAs are charged, amphiphilic salts, and have been reported to dissolve in highly polar, aqueous solvent mixtures including 100% H2O 15b and H2O/ EtOH (95:5). 13a However, molecular self-association events and the formation of larger aggregates have been observed under these conditions, which might affect the concentration and morphology of the compound to arrive at the surface of the vesicle membrane, and could preclude any active transport activity. Here, we found that SSA 1 was soluble in 100% water and investigated the aggregation properties using tensiometry, dynamic light scattering (DLS) and zeta potential measurements (Section S3). We found that SSA 1 has a critical micelle concentration (CMC) of 4.13 mM in H2O, and observed aggregates of approximately 443 nm diameter in a 5 mM solution.