Direct AFM measurements of adhesion forces between calcium oxalate monohydrate and kidney epithelial cells in the presence of Ca2+ and Mg2+ ions.

Adhesion forces between the calcium oxalate monohydrate (COM, whewellite) crystal and the layer of the epithelial kidney cells have been directly measured under buffer solutions by using atomic force microscope (AFM). Two renal epithelial lines, MDCK (a collecting duct line) and LLC-PK1 (a proximal tubular line), were used. All experiments were conducted in buffer solutions containing additional Ca(2+) and Mg(2+) ions in the various concentrations.

Adhesion force between calcium oxalate monohydrate crystal and kidney epithelial cells and possible relevance for kidney stone formation.

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.

Atomic force microscopy measurement of the elastic properties of the kidney epithelial cells.

Direct interaction force measurements using atomic force microscopy (AFM) were carried out between a silicon nitride tip and renal epithelial cells (Madin-Darby Canine Kidney-MDCK and proximal tubular epithelial cells derived from pig kidneys, LLC-PK1). The approaching (extending) portion of the force/distance curves is considered, and repulsive forces in the long range of 2-3 microm were seen in both MDCK as well as LLC-PK1 cells growing under normal conditions. The repulsive force in the shorter distance range of 50-200 nm was also observed, when cells were damaged exposing the underlying basal membrane.