Rabinovich Yakov I, Esayanur Madhavan, Daosukho Saijit, Byer Karen J, El-Shall Hassan E, Khan Saeed R
University of Florida, PO Box 6135, Gainesville, FL 32611-6135, USA.
J Colloid Interface Sci. 2006 Aug 1;300(1):131-40. doi: 10.1016/j.jcis.2006.03.070. Epub 2006 Apr 4.
AFM interaction force measurements have been performed between calcium oxalate monohydrate crystal (COM) colloidal probes and monolayers of renal epithelial cells (on a polymer substrate) in artificial urine (AU) solutions. The adhesion force was measured for the COM/MDCK cell interaction, while no adhesion force was found for the COM/LLC-PK(1) cell interaction. Long-range repulsive forces for both lines of cells were measured in the range of 2-3 mum. After removal of the cell from the substrate by the AU flow, the basal membrane (BM), with a thickness of 100-200 nm, remained on the substrate. In this case, the shorter-range repulsive forces were found on the extending (approaching) portion of force/indentation curves. Similar to the COM/MDCK cell interaction, the retracting portions of curves for COM/basal membranes have shown the existence of the attractive force of adhesion for the interaction of COM with a BM of MDCK cells, while no adhesion was found for COM/BM LLC-PK(1) cells interaction. No adhesion force was found for the interaction of a BM (of any cells) with the silicon nitride tip. Besides the hydrodynamic reasons, the adhesion difference between LLC-PK(1) and MDCK cells possibly explains the preferential deposition of crystals only in collecting ducts (lined with MDCK-type cells) and the lack of the crystal deposition in the proximal tubules (lined with LLC-PK(1)-type cells). Previous treatments of cells with oxalate alone increased the adhesion force COM/BM MDCK; however, even after oxalate treatment there was small or no adhesion between COM and BM LLC-PK(1) cells. Note that the adhesion force for COM/BM MDCK is practically independent of the probe velocity, i.e., does not have the viscous origin. Evaluation of the adhesion energy shows that this force should be related to the ionic or hydrogen bonds of samples.
在人工尿液（AU）溶液中，已对一水草酸钙晶体（COM）胶体探针与肾上皮细胞单层（在聚合物基质上）之间进行了原子力显微镜（AFM）相互作用力测量。测量了COM与MDCK细胞相互作用的粘附力，而COM与LLC-PK(1)细胞相互作用未发现粘附力。在2-3μm范围内测量了两种细胞系的长程排斥力。通过AU流将细胞从基质上移除后，厚度为100-200nm的基底膜（BM）留在了基质上。在这种情况下，在力/压痕曲线的延伸（接近）部分发现了较短程的排斥力。与COM/MDCK细胞相互作用类似，COM/基底膜曲线的回缩部分显示，COM与MDCK细胞的基底膜相互作用存在粘附吸引力，而COM/BM LLC-PK(1)细胞相互作用未发现粘附现象。未发现任何细胞的基底膜与氮化硅尖端相互作用存在粘附力。除了流体动力学原因外，LLC-PK(1)和MDCK细胞之间的粘附差异可能解释了晶体仅优先沉积在集合管（内衬MDCK型细胞）中，而在近端小管（内衬LLC-PK(1)型细胞）中缺乏晶体沉积的现象。先前单独用草酸盐处理细胞增加了COM/BM MDCK的粘附力；然而，即使经过草酸盐处理，COM与BM LLC-PK(1)细胞之间的粘附力仍然很小或不存在。请注意，COM/BM MDCK的粘附力实际上与探针速度无关，即不是由粘性引起的。粘附能的评估表明，这种力应该与样品的离子键或氢键有关。
