Harroun T A, Nieh M-P, Watson M J, Raghunathan V A, Pabst G, Morrow M R, Katsaras J
National Research Council, Steacie Institute for Molecular Sciences, Chalk River, Ontario, Canada K0J 1J0.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Mar;69(3 Pt 1):031906. doi: 10.1103/PhysRevE.69.031906. Epub 2004 Mar 19.
Using neutron diffraction and a specially constructed high pressure cell suitable for aligned multibilayer systems, we have studied, as a function of pressure, the much observed anomalous swelling regime in dimyristoyl- and dilauroyl-phosphatidylcholine bilayers, DMPC and DLPC, respectively. We have also reanalyzed data from a number of previously published experiments and have arrived at the following conclusions. (a). The power law behavior describing anomalous swelling is preserved in all PC bilayers up to a hydrostatic pressure of 240 MPa. (b). As a function of increasing pressure there is a concomitant decrease in the anomalous swelling of DMPC bilayers. (c). For PC lipids with hydrocarbon chains >or=13 carbons the theoretical unbinding transition temperature T small star, filled is coupled to the main gel-to-liquid crystalline transition temperature T(M). (d). DLPC is intrinsically different from the other lipids studied in that its T small star, filled is not coupled to T(M). (e). For DLPC bilayers we predict a hydrostatic pressure (>290 MPa) where unbinding may occur.
利用中子衍射以及一个专门构建的适用于取向多层体系的高压池，我们分别研究了二肉豆蔻酰磷脂酰胆碱（DMPC）双层膜和二月桂酰磷脂酰胆碱（DLPC）双层膜中常观察到的反常膨胀现象与压力的关系。我们还重新分析了一些先前发表的实验数据，并得出以下结论：（a）描述反常膨胀的幂律行为在所有磷脂酰胆碱双层膜中都能保持到240兆帕的静水压力。（b）随着压力增加，DMPC双层膜的反常膨胀会随之降低。（c）对于碳氢链含≥13个碳的磷脂酰胆碱脂质，理论上的解束缚转变温度T*，实心与主要的凝胶态到液晶态转变温度T(M)相关联。（d）DLPC与其他研究的脂质本质上不同，其T*，实心与T(M)不相关联。（e）对于DLPC双层膜，我们预测在静水压力（>290兆帕）下可能会发生解束缚。
