单分子膜诱导下尿大分子对草酸钙晶体物相和晶面的调控作用

采用SEM,XRD和FTIR手段比较研究了DPPC单分子膜诱导下尿大分子硫酸软骨素A(C₄S)、硫酸软骨素C(C₆S)和血清蛋白(SA)对尿石盐草酸钙晶体生长的影响.DPPC单分子膜不但优先选择一水草酸钙(COM)物相成核生长,而且优先选择COM的(101)晶面.没有添加剂时,得到的COM为三维的六棱柱和三维的菱形晶体;加入尿大分子抑制剂后,COM的(101)晶面进一步加强,其它晶面减弱,导致二维晶体的形成.COM的(101)晶面为富钙离子晶面,带有过剩的正电荷,而DPPC单分子膜头基带有负电荷,几种尿大分子在实验条件下亦带有负电荷,带负电荷的单分子膜及带负电荷的大分子共同作用于富钙离子的(101)晶面,使得COM的(101)晶面择优生长.C₄S,C₆S和SA的存在均能有效地抑制COM生长.

Modulation of Urinary Macromolecules Induced by DPPC Monolayers on Morphology and Crystal Face of Calcium Oxalate Crystals

The effect of urinary macromolecules such as chondroitin sulfate A(C 4S), chondroitin sulfate C(C 6S) and serum albumin(SA) on urinary crystal calcium oxalate grown beneath dipalmitoylphosphatidylcholine (DPPC) monolayer was investigated by using scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared analysis(FTIR). Only the calcium oxalate monohydrate (COM) was nucleated and grown beneath the monolayer with the (101) face oriented preferentially towards the monolayer interface. On the monolayer in the absence of additives, the tri-dimensional prismy COM crystals precipitated. However, the (101) face of COM was doubly strengthened and the other faces were weakened in the presence of urinary macromolecule inhibitors. This leads to the formation of two-dimensional plate-like COM crystals. The result is attributed to the interaction between the positively charged calcium-rich (101) face of COM with the negative-charged headgroups of the monolayer and the negatively charged macromolecules. All the three additives can inhibit the growth of COM crystals.