| Cell membrane as a protective barrier,provide a stable internal environment and a variety of catalytic reaction active site,involved in the material transport,information recognition and energy conversion process between cells and environment,what’s more,it plays an important role in the survival,growth,reproduction and differentiation of cells.Biomimetic membrane systems obtained to simulate the structural characteristics of natural cell membranes have been widely used in agricultural,industrial and biomedical fields.In particular,the single-molecule detection technology developed by combining biomimetic membrane with nanochannels has the advantages of high throughput,low cost,label-free and real-time rapid detection,which makes this technology emerge in the fields of clinical medicine and life science.As is well known,the unsupported lipid bilayer membrane with poor stability and short service life make it difficult to achieve commercial performance,and its symmetrical structure is difficult to reflect the structural characteristics of cell membrane asymmetry.Although an increasing number of researchers use polymer membranes with strong mechanical stability instead of unstable lipid membranes,to our knowledge,few studies have used them for single-molecule detection.Based on this,this paper utilizes the polydopamine(PDA)has good biocompatibility,biodegradable ability,adhesion,etc.,and is combined with a single layer of phospholipid membrane to prepare a stable and asymmetric novel bionic hybrid membrane,which is used for single molecule detection through embedded nanochannel.The details of this study are as follows:1.Preparation and study of polymer monolayer film formed at the air/water interface In this study,stable PDA/polyethyleneimine(PEI)polymer monolayers were successfully prepared and characterized,which demonstrated that PEI participates in PDA reaction and covalent polymerization with it.The method of forming a polymer-polymer bilayer bionic film with high stability,excellent sealing,and tolerance to the high pressure of 900 m V was established.2.Construction of plane unsupported novel bionic membrane and insertion of protein channelIn this chapter,the assembly of PDA/PEI polymer monolayers with lipid monolayers to form novel biomimetic hybrid membranes was investigated.The biomimetic hybrid membrane has asymmetric structure,superior mechanical stability,excellent sealing,life is at least 6 times of the lipid bilayer membrane,the maximum breakdown voltage can reach540 m V,and has a certain anti-interference and anti-vibration ability,well solve the existing problems of lipid bilayer membrane.More importantly,this biomimetic hybrid membrane retains the fluidity of the phospholipid membrane,which can be quickly embedded in protein channels and kept stable in the hybrid membrane.The presence of polymer has no impact on the inherent properties and noise of the channel,which provides a new idea for the development of cell imitation membrane.3.Single-molecule detection of nanopore based on the biomimetic hybrid membrane In this study,the application of single-molecular analysis of protein nanochannels based on polymer hybrid bionic membrane was studied By comparing with the results of single molecule detection in lipid bilayer membrane,it is found that the presence of polymer does not affect the recognition and detection of analytes by protein channels,and this new biomimetic hybrid membrane can completely replace lipid membrane for single molecule analysis.Moreover,the unique properties of the membrane,such as the charge on the polymer surface,provide different sensitivity for different analyte detection. |
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