Development of an instrument to measure adhesion of calcium oxalate monohydrate to surfaces.

摘要

Calcium oxalate monohydrate (COM) is the primary constituent in kidney stones. COM crystals were synthesized in the laboratory and characterized. Computer calculations of particle shape have been reconciled to observed shapes of COM crystals experimentally synthesized under various conditions. Comparison between the theoretical atomic structures generated by computer calculations are consistent with previously reported atomic layering sequences.; Composite mixing rules were used to deconvolute the dielectric constant of COM from a COM/silicone composite. Utilizing the Lichtenecker dielectric mixing model, the value of the static dielectric constant of COM was determined to be 28.9. Optical and dielectric data were then used in the Tabor-Winterton relationship to calculate the Hamaker constant, A{dollar}sb{lcub}131{rcub}{dollar}, of COM particles interacting in water. The A{dollar}sb{lcub}131{rcub}{dollar} for COM as a function of crystallographic habit also was examined. The mean value of A{dollar}sb{lcub}131{rcub}{dollar} for COM was calculated to be {dollar}13.7 times 10sp{lcub}-21{rcub}{dollar} J at 37{dollar}spcirc{dollar}C in an aqueous environment.; A hydrodynamic method for measuring the adhesion of particles to a surface has been designed for use in the study of kidney stone disease and other pathological biomineralization phenomena. The hydrodynamic force required to displace a particle adhering to a fused quartz substrate was calculated via the Poiseuille equation. The strength necessary to remove 50% of the COM particles adhering to the substrate on the (010) and (101) crystallographic surfaces are 81 and 170 Pa, respectively. The previously determined Hamaker constant and measured values of zeta potential were used to calculate the energy of interaction between a COM particle and the fused quartz substrate which was found to be comparable to experimentally measured values, provided the separation distance was on the order of 20 nm.; Using the instrument and technique developed, the adhesion of COM to biologically and non-biologically relevant materials was measured in COM saturated solution and in an artificial urine ion solution. The biologically significant materials were the proteins collagen type I, fibronectin, and MATRIGEL{dollar}spcircler{dollar} a mixture of basement membrane proteins. The non-biologically relevant material was polyethyleneimine a positively charged macromolecule used as a control. MATRIGEL{dollar}spcircler{dollar} and the positive control, polyethyleneimine, exhibited the highest adhesion to COM crystals.