Preparation of supported lipid bilayer membranes by thin film extrusion / 中国组织工程研究

ABSTRACT

BACKGROUND: The artificial supported lipid bilayer membrane is the most similar in vitro biomimetic model of the cell membrane. The artificial high-quality lipid bilayer membrane will provide a critical tool for the study of the microstructure of biological membranes, cell signal transduction, biofilm sensors and drug carriers.OBJECTIVE: To explore the optimal preparation conditions of the lipid bilayer membrane with uniform surface and high mobility and its detection indexes.METHODS: By thin film extrusion, liposomes were filtrated 10 times through the filter membrane with the pore diameter of 0.1 and 0.2 μm respectively, with the unfiltered sample as control. The root mean squared roughness of lipid bilayer membrane was detected by atomic force microscopy to explore the optimal pore diameter of the filter membrane for preparation of the lipid bilayer membrane with high uniformity. 160 μL egg-PC (10 g/L) and 5, 10 or 25 μL NBD-PC were mixed separately. The mobility of lipid bilayer membrane was detected by fluorescence recovery after photobleaching (FRAP) to explore the optimal proportion of egg-PC and NBD-PC.RESULTS AND CONCLUSION: The results of atomic force microscopy showed that the lipid bilayer membrane through the 0.1 μm filter membrane had the highest degree of uniformity (P <0.01), with the root mean squared roughness of(0.432±0.181) nm. By using the filter membrane whose pore diameter was greater than 0.1 μm, the surface uniformity of the lipid bilayer membrane was poor and there were more liposome vesicles on the surface. The FRAP results showed that the lipid bilayer membrane through the 0.1 μm filter membrane had a higher degree of fluorescence recovery. When 160 μL egg-PC (10 g/L) and 10 μL NBD-PC were mixed and filtrated through the 0.1 μm filter membrane, the degree of fluorescence recovery of the lipid bilayer membrane reached 90% and the diffusion coefficient was greater than 1 μm2/s which met the standard of high-quality lipid bilayer membrane. These results suggested the optimum ratio of egg-PC to NBD-PC and the optimum filter membrane pore size for preparation of the lipid bilayer membrane by thin film extrusion.