Photo- and Redox-Regulated Transmembrane Ion Transporters.

Synthetic supramolecular ion transporters find applications as potential therapeutics and as tools for engineering functional membranes. Stimuli-responsive systems enable external control over transport, which is necessary for targeted activation. The Minireview provides an overview of current approaches to developing stimuli-responsive ion transport systems, including channels and mobile carriers, that can be controlled using photo or redox inputs.

Inter-Vesicle Signal Transduction Using a Photo-Responsive Zinc Ionophore.

Transmission of chemical information between cells and across lipid bilayer membranes is of profound significance in many biological processes. The design of synthetic signalling systems is a critical step towards preparing artificial cells with collective behaviour. Here, we report the first example of a synthetic inter-vesicle signalling system, in which diffusible chemical signals trigger transmembrane ion transport in a manner reminiscent of signalling pathways in biology. The system is derived from novel ortho-nitrobenzyl and BODIPY photo-caged ZnII transporters, in which cation transport is triggered by photo-decaging with UV or red light, respectively. This decaging reaction can be used to trigger the release of the cationophores from a small population of sender vesicles. This in turn triggers the transport of ions across the membrane of a larger population of receiver vesicles, but not across the sender vesicle membrane, leading to overall inter-vesicle signal transduction and amplification.