Artificial K⁺ Channels Formed by Pillararene‐Cyclodextrin Hybrid Molecules: Tuning Cation Selectivity and Generating Membrane Potential

Abstract

Ac lass of artificial K + channels formed by pillararene-cyclodextrin hybrid molecules have been designed and synthesized.T hese channels efficiently inserted into lipid bilayers and displayed high selectivity for K + over Na + in fluorescence and electrophysiological experiments.The cation transport selectivity of the artificial channels is tunable by varying the length of the linkers between pillararene and cyclodexrin. The shortest channel showed specific transmembrane transport preference for K + over all alkali metal ions (selective sequence:K + > Cs + > Rb + > Na + > Li + ), and is rarely observed for artificial K + channels.T he high selectivity of this artificial channel for K + over Na + ensures specific transmembrane translocation of K + ,a nd generated stable membrane potential across lipid bilayers.

pH‐Dependent Chloride Transport by Pseudopeptidic Cages for the Selective Killing of Cancer Cells in Acidic Microenvironments

“…Thus,t he fastestr atea nd higheste ffecto ft he acid medium waso bserved with thef luorinated cage 1c.T his result wasa lsoc onfirmed by monitoring chloride influx using lucigeninf luorescent dye [13c] (SupportingI nformation,. Additional experimentsw ithv esiclesl oadedw ith ar atiometric fluorescentp robe sensitivet op H( HPTS) [14] proved that thesecompounds efficientlydissipate pH gradients (Figure2B).T he relativee fficiencyc orrelatedw ellw itht he relative chloride-transport activity measured usingI SE and lucigeninassays. Overall, theresults suggestanH + /Cl À symport mechanismf or cages 1a-c that is facilitatedb ya cidicm edia ands tronglyd ependent on then atureo ft he host side chain.…”

“…Thei onophoric activity of compounds 1a-e was first explored in model phospholipid bilayers by using POPC liposomes ( Figure 2). [13,14] First, the ability of these compounds to facilitate chloride efflux from chloride-loaded vesicles was monitored using ac hloride-selective electrode (ISE). [13a] Theliposome suspension was placed in an isotonic, chloride-free medium and the studied cages were added as aliquots of stock DMSO solutions.Percent chloride efflux for each compound was monitored over time,since the release of all encapsulated chloride by addition of ad etergent allowed the normalization of the chloride leakage.U nspecific detergent effects induced by these compounds were ruled out with control experiments in vesicles loaded with carboxyfluorescein [13d] (Supporting Information, Figure S62).…”

Macrocycle-Based Synthetic Ion Channels

“…Phe-based tripeptides were attached to the macrocycle to improve its membrane penetration ability. Tripeptide appended with hydrazide macrocycles 51-52 were also prone to form tubular structure in lipid bilayer similar to the PA scaffold through the multiple intramolecular H-bonding [78]. Patch clamp experiments reveal that both the macrocycles could transport all alkali metal cations that follow Eisenman I sequence (NH 4 + > Cs + > Rb + > K + > Na + ).…”

Novel fluorescent supramolecular polymer metallogel based on Al3+ coordinated cross‐linking of quinoline functionalized‐ pillar[5]arene act as multi‐stimuli‐responsive materials

“…By integrating pillar[n]arene derivatives into supramolecular systems, supramolecular systems could be incorporated with intrinsic advantages of pillar[n]arenes. So far, pillar[n]arenes‐based supramolecular polymer gels, as a supramolecular smart material, have been widely investigated because of their inherent optoelectronic properties coming from their chromophores and extensive applications in sensing, organic electronic devices harvesting, biomedical engineering and so on . However, most supramolecular polymer gels need tedious and costly construction processes.…”