Brewster angle microscopy of calcium oxalate monohydrate precipitation at phospholipid monolayer phase boundaries.
Brewster angle microscopy of calcium oxalate monohydrate precipitation at phospholipid monolayer phase boundaries.
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DOI：
10.1021/la0488194
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发表时间：
2004-08
期刊：
影响因子：
--
通讯作者：
Isa O. Benitez;D. Talham
中科院分区：
文献类型：
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作者：
Isa O. Benitez;D. Talham
借助布鲁斯特角显微镜原位观察到一水草酸钙（COM）在局限于空气/水界面的磷脂单层上的沉淀。COM晶体表现为明亮的物体，易于识别和量化，以评估不同条件对结晶的影响。在1，2-二棕榈酰-sn-甘油基-3-磷酸胆碱（DPPC）的单层中，在液体冷凝（LC）和液体膨胀（LE）相中监测晶体沉淀。在LC相内，较高的压力降低了界面处结晶的发生率，这意味着在该相内沉淀通过单层的较高的可压缩性或流动性而增强。还研究了双相LC/LE和LE/气体（G）单层的沉淀。COM优先出现在DPPC LC/LE和LE/G单分子膜的相边界处。然而，当LC/LE相边界由相分离的两种不同磷脂（例如DPPC和1，2-二肉豆蔻酰-sn-甘油-3-磷酸胆碱）产生时，晶体形成远离DPPC LC相内的界面。有人建议，COM生长在相界是优选的，只有当有分子交换之间的阶段。
The precipitation of calcium oxalate monohydrate (COM) at phospholipid monolayers confined to the air/water interface is observed in situ with the aid of Brewster angle microscopy. COM crystals appear as bright objects that are easily identified and quantified to assess the effects of different conditions on crystallization. Crystal precipitation was monitored at monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in liquid condensed (LC) and liquid expanded (LE) phases. Within the LC phase, higher pressures reduce the incidence of crystallization at the interface, implying that within this phase precipitation is enhanced by higher compressibility or fluidity of the monolayer. Precipitation at biphasic LC/LE and LE/gas (G) monolayers was also studied. COM appears preferentially at phase boundaries of the DPPC LC/LE and LE/G monolayers. However, when an LC/LE phase boundary is created by two different phospholipids that are phase segregated, such as DPPC and 1,2-dimyristoyl-sn-glycero-3-phosphocholine, crystal formation occurs away from the interface within the DPPC LC phase. It is suggested that COM growth at phase boundaries is preferred only when there is molecular exchange between the phases.