Based Synthesis And Properties Of The The The Crown Ethers Supramolecular Self-assembly Of Artificial Ion Channels

As known, ion channel is a special class of micropore in the cell membrane constructed by hydrophilic membrane protein, which plays an important role to the metabolic activity of living cells, and exchange of substance with the extracellular environment. The abnormalities of their structures and functions often cause thousands of illnesses, which are generally called ion channel diseases. For the moment, these diseases cannot be checked by conventional instruments, which make it difficult for the diagnosis. Therefore, the use of artificial ion channels obtained by means of chemical synthesis, to simulate the structure and function of ion channels in vivo cell membrane, will have great theoretical and practical significance for in-depth study of these diseases and discovery of specific therapy drugs. Our work in this paper mainly involved two parts as described below:1 Design and synthesis of novel azobenzene photoresponsive artificial ion channelBenzocrownether derivatives were designed and synthesized. Here, two points should be considered:1) Some functional groups that generate non-covalent bond interactions was introduced on purpose, such as complementeary hydrogen bonds,Ï€-Ï€or electrostatic adsorption interactions, which made the molecules self-assemble into tubular structure with a suitable diameter; 2) Suitable hydrophobic groups should be introduced to regulate the amphiphilic property of the molecule, which made them self-assemble in the phospholipid bilayer member to form ion channels. Artificial ion channel with excellent ion selectivity,high ion transmission rate and conductivity was optimized finally by adjusting the diameter of the ion channel and the structure of the substituent groups. Additionally, photoresponsive azobenzene group was introduced as the photoswitch to control the on/off of the ion channel via the large changes of azobenzene's structure and dipole induced by cis-trans isomerization.2 Design and synthesis of artificial ion channel based on rid-rod moleculesA series of rigid rod oligomers using 1,4-phenyleneethynylene as repeating unit was designed and some of the intermediates have been synthesized. Based on the inherent rigid property and the introduction of appropriate non-covalent bond interaction of the oligomer, the crown ether molecules in the one side of the oligomer arrayed into channel. The length of rigid oligomer was controlled to match with the thickness of the lipid bilayer membrane by controlling the number of the repeating units, which helped the oligomers embed in to the membrane to form ion channel. And the introduction of different crown ether groups made the formed ion channels transported different ions selectively.