缺陷LB膜诱导草酸钙晶体的生长

Crystal Growth of Calcium Oxalate Induced by Defective Langmuir-Blodgett Films

肾结石形成与肾上皮细胞膜损伤密切相关,但细胞膜损伤后的微结构及其与肾结石微晶粘附的分子机制仍不清楚,本文采用经草酸钾处理后存在缺陷的二棕榈酰磷酯酰胆碱(DPPC)的LB膜为模型,采用原子力显微镜(AFM)、荧光显微镜和扫描电子显微镜(SEM)研究了模型膜的缺陷畴区及其对一水草酸钙(COM)晶体生长的促进作用,LB膜内圆形的缺陷畴区可以诱导圆形COM晶体图形生成,圆形晶体图形的直径从3μm到150μm不等。在圆形区域内,单个COM晶体的尺寸大都在1～3μm,以针状、四边形或不规则的形状存在;而在同等条件下正常LB膜诱导的COM晶体没有圆形聚集现象,单个COM晶体在LE/LC相边界生长,其尺寸显著增加至5～10μm.不同性质LB膜促进COM成核和生长的强弱依次为:经草酸钾处理的LB膜缺陷畴区>>正常LB膜的LC/LE边界>正常LB膜非边界区域>>无膜诱导。从缺陷LB膜的活性位点及其对COM晶体成核的促进作用等方面讨论了上述实验结果.

Urolithiasis is related to injuries of renal epithelial membrane. However, the microstructure of injured renal epithelial cellular membranes and the mechanism for the adherence of stone microcrystals have not been yet clearly understood. The defect formation of Langmuir-Blodgett （LB） film of 1,2-dipalmitoylsn-glycero-3-phosphocholine （DPPC） injured by potassium oxalate was investigated with the aid of atomic force microscopy （AFM） and fluorescent microscopy. The effect of the defects on the growth of calcium oxalate monohydrate （COM） was investigated by scanning electronic microscopy （SEM）. The circular defects in the LB film could induce circular aggregation of COM. The diameter of the circular patterns ranged from 3 to 150μm. In the patterns, the COM crystals existed as needle-like, quadrangle and anomalistic shape with a size of about 1～3 μm. However, no circular patterns of COM crystals were formed if the LB films had not been treated with oxalate. In this case the COM crystals with a size of about 5～ 10 μm randomly grew at the LE/LC boundaries of the LB films. The effect of various LB films on the nucleation and growth of COM crystals follows the order： the LB film with defects treated by potassium oxalate〉〉LC/LE boundaries in normal LB film〉normal LB film except the LC/LE boundaries〉〉bulk solution. The above results were discussed from the points of active sites in the defective LB films and their effect on COM nucleation.