Counterion-activated polyions as soft sensing systems in lipid bilayer membranes: from cell-penetrating peptides to DNA

Abstract

Activated by amphiphilic anions, cationic oligo- and polymers can phase transfer into and across bulk and lipid bilayer membranes. In biology, this system accounts for the voltage gating of ion channels and the ability of cell-penetrating peptides (CPPs) to cross membrane barriers. In soft nanotechnology, the same system has been used for multianalyte sensing in complex matrices (cholesterol sensing in blood and eggs, for example). Would inversion of all involved charges provide access to similarly versatile functional supramolecular systems? Activation of polyanions by amphiphilic cations is well known as the basis of non-viral gene transfection. Could DNA/RNA nanotechnology thus be applied to produce smart, stimuli-responsive cation transporters that can function as multianalyte sensing in fluorogenic vesicles? Preliminary results suggest that the answer to these questions will be yes.