Construction Of Functionalized Pillar[5]arene Channels And Study Of Ion Transport Properties

Biological ion channels formed by proteins embedded in the cell membrane exist in all living systems.They used to intelligently regulate the various ions passing through the cell membrane,play a vital role in the process of life.Ion channels are also important targets for drug discovery.The breakdown of ion channels can lead to some diseases,including diabetes,epilepsy,cystic fibrosis,arrhythmia and so on.Therefore,ion channels have become important objects of research.Inspired by smart biological ion channels,the construction of bionic smart nanopores and nanochannels with smart ion transport characteristics like biological ion channels has aroused widespread research interest.Different from fragile biological ion channels,artificial solid nanopores and nanochannels have mechanical and chemical stability,controllable channel shapes and customizable surface properties.These advantages make them very useful in a wide range of practical applications.However,the size of bionic ion channels constructed by most of the current work is in the nanometer scale,while the size of biological ion channels is generally less than 1 nm.The angstrom-scale structure of biological ion channels makes functional ion transport characteristic.The construction of sub-nanometer size biomimetic ion channels is a challenging task.Therefore,in the work of this thesis,further bionic research on the imitation of the size of biological ion channels was carried out,a bionic ion channel with sub-nanometer size was constructed,and the transport characteristics of particles were studied.This is very helpful for exploring the performance of biological ion channels,and it also deepens the understanding of the relationship between ion channel structure and function.The dissertation contains three parts as following:1.Biological proton channel has ultra-high proton selectivity.It is of great significance to develop artificial proton channels with biological proton selectivity.To construct an artificial proton channel with the size of angstroms to realize the selective transport of protons is a challenging task.We start from imitating the structure of the biological proton channel,by assembling the negatively charged thioglycolic acid and the positively charged pillar[5]arene layer by layer,forming a pillar[5]arene molecular assembly channel at the interface,and further using polymethyl phenylene(PMMA)polymer coated the channels,and the interface is finally removed to form a self-supporting film doped with pillar[5]arene channels.And the selective transport properties of the pillar[5]arene channels for protons were studied.By comparing with the PMMA membrane that is not doped with pillar[5]arene channels,it can be concluded that the pillar[5]arene channels with the angstrom size has high proton selectivity.This highly proton selective channel provides a certain research foundation for the development of proton conductive solid materials.2.Artificial proton channels with directional proton transport properties have a wide range of applications in nanofluid ion diodes,including biosensing and energy conversion.Inspired by the heterogeneous pore structure of the biological proton channel with the size of angstroms,on the basis of the previous work,we further adjusted the number of pillar[5]arene assembly layers to obtain pillar[5]arene channels with different charges at both ends,further mimicking the biological proton channel of asymmetric structure.On this basis,the directional transmission performance of pillar[5]arene channels to protons was studied.3.Based on the work of the previous two chapters,by covalently modifying dopamine molecules with copper ion responsiveness on the pillar[5]arene channels,a bionic copper ion channel with selective response to copper ions was constructed.This channel realized specific response and reversible regulation to copper ions,has potential application value in medical diagnosis.