Study And Regulation Of Membrane Properties Based On Cell Membrane Vesicles

Cell membrane plays an important role in various physiological activities such as material exchange,energy conversion,and signal transmission between the cell and the external environment.Therefore,it's of great importance to study the structures and properties of cell membrane for understanding the vital activities realted to cell membrane surface.At present,researchers mainly ultilize lipsomes as cell membrane models to carry out correlational studys,which lack of the fildty and integrity of natural cell membrane.In this paper,we use cell membrane vesicles(GMVs)extracted from living cells as a model to study the effect of different salt ions concentrations on membrane permeability,and construct an artificial ion cha nnel in membrane by the advantage of DNA nanostructures.The specific research content is as follows:In chapter 2,since the importance of cell membrane permeability on biological activities and drug development,the current research on membrane permeability mainly has two directions,one is the use of phospholipid membranes consisted of phospholipids and cholesterol as research model to study the effect of cholesterol and phospholipids on membrane permeability;t he second is to study the effect of different external environments and solute properties on cell membrane permeability.We used vesicles extracted from living cells as a research model and studied the change of the membrane permeability by altering the concentration of Na~+in solution.We explored the permeability of different dyes to GMVs by confocal microscopy and quantizied the fluorencent intensity using Image J software.The results sh owed that the concentration of ions did had a significant effcet on membrane permeability.With the change of concentration of Na~+outside membrane,the positively charged malachite green molecule entering the vesicle remarkably changed,while there was no obvious change for the uncharged rhodamine B.Meanwhile,a certain concentration of Na+can accelerate malachite green molecules into vesicles.In Chapter 3,We used DNA nanopores to construct the responsive bionic ion channels in vesicle.DNA nanopores labelled with cholesterol were obtained by self-assembly.Then the DNA nanopores were anchored in membrane through the hydrophobic interaction between cholesterol and membrane.In this design,the top of nanopore can be blocked by a“lock”strand where ions couldn't flow past.Only after“lock”strand is hybrided with“key”strand and released from nanopore,nanopore is open to allow ions to pass through,thus regulating the influx of ions.T aking calcium ions as a model,the results show that the DNA nanochannels we designed can effectively control the entry of calcium ions into the vesicles.