Stable Lipid Bilayers Used For The Single Molecule Analysis Of Nanopore

Lipid bilayer is a kind of classical interfacial material.The unique bilayer structure is highly similar to the biofilm.Because of its simple structure,it is often used as a simulation tool to study the characteristics of biomolecules,which makes it have an irreplaceable position in the field of biomolecule research.In addition,lipid bilayer also display good prospects in biological imaging technology,targeted drug delivery and drug delivery.Nanopore sensing technology based on lipid bilayer has been used in DNA sequencing,enzyme activity detection,disease diagnosis and so on.However,lipid bilayer is maintained by the non-covalent bond between phospholipid molecules,and the weak intermolecular force leads to poor membrane stability,so it is particularly important to improve the stability of the phospholipid bilayer.In this paper,a new nanopore detection system was established.The lipid bilayer was constructed between the electrolyte and the agar gel interface,and the ?-hemolysin was successfully assembled on the lipid bilayer.The cell for nanopore detection has been simplified,and the detection of DNA molecules has been achieved.The development of this technology has benn limited because lipid bilayer was instability.We have tried to enhance the stability of lipid bilayer by coating polydopamine films on lipid bialyer.The main research contents are as follows:1.The establishment of a new nanopores detection systemIn the new nanopore detection system,lipid bilayer exists in the interface of the electrolyte solution and the gel.First,because phospholipid are amphiphilic,whose head is hydrophilic while tail hydrophobic.A lipid monolayer with the head facing the gel and the tail facing the air is formed at the air-gel interface.Then another lipid monolayer with the head facing the electrolyte solution and the tail facing the air is formed at the air-electrolyte.When two lipid monolayers approach each other,lipid bilayer can form spontaneously at the interface.The protein pores ?-hemolysin in the solution can assemble on lipid bilayer to form a gel-supported transmembrane protein nanopore electrode.This electrode has been applied to test single molecule of cyclodextrin and DNA.Based on the new principles of building lipid bilayer,gelsupported transmembrane protein nanopore electrode has the characteristic of simple structure(It do not need polytetrafluoroethylene film with holes when establish lipid bilayer)and easy to use(It can test analytes by insert into solution directly).It is expected to realize nanopore technology out of the laboratory and provided a new ideas to nanopore research.2.Improved stability of polydopamine-supported phospholipid bilayerThe instability of the lipid bilayer has always been one of the decisive factors that limit the nanopore single-molecule technology to go out of the laboratory.In order to improve the instability of the lipid bilayer,based on the characteristic of polydopamine,a polydopamine protecting lipid bilayer has been made.The formation conditions and the kinetics of the interaction between polydopamine and lipid bilayer were studied.The results showed that polydopamine can build up the stability of lipid bilayer significantly.