tailieunhanh - Báo cáo hóa học: " Mechanics of lipid bilayer junctions affecting the size of a connecting lipid nanotube"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Mechanics of lipid bilayer junctions affecting the size of a connecting lipid nanotube | Karlsson et al. Nanoscale Research Letters 2011 6 421 http content 6 1 421 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Mechanics of lipid bilayer junctions affecting the size of a connecting lipid nanotube Roger Karlsson1 Michael Kurczy2 Richards Grzhibovskis3 Kelly L Adams4 1 Andrew G Ewing1 Ann-Sofie Cans2 and Marina V Voinova5 Abstract In this study we report a physical analysis of the membrane mechanics affecting the size of the highly curved region of a lipid nanotube LNT that is either connected between a lipid bilayer vesicle and the tip of a glass microinjection pipette tube-only or between a lipid bilayer vesicle and a vesicle that is attached to the tip of a glass microinjection pipette two-vesicle . For the tube-only configuration TOC a micropipette is used to pull a LNT into the interior of a surface-immobilized vesicle where the length of the tube L is determined by the distance of the micropipette to the vesicle wall. For the two-vesicle configuration TVC a small vesicle is inflated at the tip of the micropipette tip and the length of the tube L is in this case determined by the distance between the two interconnected vesicles. An electrochemical method monitoring diffusion of electroactive molecules through the nanotube has been used to determine the radius of the nanotube R as a function of nanotube length L for the two configurations. The data show that the LNT connected in the TVC constricts to a smaller radius in comparison to the tube-only mode and that tube radius shrinks at shorter tube lengths. To explain these electrochemical data we developed a theoretical model taking into account the free energy of the membrane regions of the vesicles the LNT and the high curvature junctions. In particular this model allows us to estimate the surface tension coefficients from R L measurements. Background Membrane tethers have been studied extensively over the past 40 years 1-11 . These structures .