Bilayer thickness and lipid interface area in unilamellar extruded 1,2-diacylphosphatidylcholine liposomes:: a small-angle neutron scattering study
Bilayer thickness and lipid interface area in unilamellar extruded 1,2-diacylphosphatidylcholine liposomes:: a small-angle neutron scattering study
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DOI：
10.1016/s0005-2736(01)00298-x
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发表时间：
2001-05-02
影响因子：
3.4
通讯作者：
Uhriková, D
中科院分区：
文献类型：
--
作者：
Balgavy, P;Dubnicková, M;Uhriková, D
用小角中子散射（SANS）方法研究了由1，2-二月桂酰磷脂酰胆碱（DLPC）、1，2-二肉豆蔻酰磷脂酰胆碱（DMPC）和1，2-二硬脂酰磷脂酰胆碱（DSPC）在重水中通过500埃孔径的聚碳酸酯滤膜挤出制备的大单层脂质体。假设脂质体为球形且具有高斯半径分布，使用双层中子散射长度密度的阶跃函数模型拟合对应于小于或等于0.0015埃（-2）的散射矢量Q和小于或等于0.0115埃（-2）的Q（2）的区域中的中子散射强度J（0）。利用脂质体积数据，并假设双层极性区的厚度等于d（H）= 9 +/-1埃，并且在双层极性区中注入的水分子体积与在含水本体水相中注入的水分子体积相同，则空间双层厚度d（L），获得脂质表面积A（L）和嵌入双层极性区域中的每个脂质分子的水分子数N：在20 ℃的DLPC中，d（L）= 41.58 +/- 1.93埃，A（L）= 57.18 +/- 1.00埃（-2）和N = 6.53 +/- 1.93。d（L）= 44.26 +/- 1.42埃。在DMPC中在36 ℃下A（L）= 60.01 +/- 0.75埃（2）和N = 7.37 +/- 1.94，在DSPC中在60 ℃下d（L）= 49.77 +/- 1.52埃，8.67 +/- 1.97。在将被毛面积热膨胀系数α校正为0.00417 K-1之后，脂质表面积显示在60 ℃下随着脂质酰基链长度而减小：DLPC中A（L）= 67.56 +/- 1.18埃（2），DMPC中A（L）= 06.33 +/- 0.83 A（L），DSPC中A（L）= 64.78 +/- 0.46埃（2）。它还表明，SANS和小角X-射线散射单层脂质体的联合评价可以用来获得dH值和从双层烃区域d（HI）的脂质磷酸基团的距离。(C)2001爱思唯尔科技有限公司。保留所有权利。
Small-angle neutron scattering (SANS) experiments hale been performed on large unilamellar liposomes prepared from 1,2-dilauroylphosphatidylcholine (DLPC), 1,2-dimyristoyl-phosphatidylcholine (DMPC) and 1,2-distearoylphosphatidyl-choline (DSPC) in heavy water by extrusion through polycarbonate filters with 500 Angstrom pores. The neutron scattering intensity J(O) in the region of scattering vectors Q corresponding to 0.0015 Angstrom (-2) less than or equal to Q(2) less than or equal to 0.0115 Angstrom (-2) was fitted using a step function model of bilay er neutron scattering length density and supposing that the liposomes are spherical and have a Gaussian distribution of radii. Using the lipid volumetric data, and supposing that the thickness of bilayer polar region equals to d(H) = 9 +/- 1 Angstrom and the water molecular volume inrercalated in the bilayer polar region is the same as in the aqueous bulk aqueous phase, the steric bilayer thickness d(L), the lipid surface area A(L) and the number of water molecules per lipid molecule N intercalated in the bilayer polar region were obtained: d(L) = 41.58 +/- 1.93 Angstrom, A(L) = 57.18 +/- 1.00 Angstrom (-2) and N = 6.53 +/- 1.93 in DLPC at 20 degreesC. d(L) = 44.26 +/- 1.42 Angstrom. A(L) = 60.01 +/- 0.75 Angstrom (2) and N = 7.37 +/- 1.94 in DMPC at 36 degreesC, and d(L) = 49.77 +/- 1.52 Angstrom, 8.67 +/- 1.97 in DSPC at 60 degreesC. After correcting fur area thermal expansivity alpha similar to0.00417 K-1, the lipid surface area shows a decrease with the lipid acyl chain length at 60 degreesC: A(L) = 67.56 +/- 1.18 Angstrom (2) in DLPC, A(L) = 06.33 +/- 0.83 A(L) in DMPC and A(L) = 64.78 +/- 0.46 Angstrom (2) in DSPC. It is also shown that a joint evaluation of SANS and small-angle X-ray scattering on unilamellar liposomes can be used to obtain the value of dH and the distance of the lipid phosphate group from the bilayer hydrocarbon region d(HI). (C) 2001 Elsevier Science B.V. All rights reserved.