The study of calcium oxalate kidney stone growth in microfluidic channel

Abstract

Kidney stone disease influences 10% of people in the world [36]. Calcium oxalate (CaOx) stones are the most common stones found in the kidney stone. In this research, ANSYS/Fluent CFD was used to determine the supersaturation profile in the microchannel for different constant flow rates and Ca and Ox inlet concentrations. The growth of the CaOx stones is studied by performing experiments in a microfluidic channel under an optical microscopy. The growth of the CaOx stones is also investigated by using a combined transport-kinetics model which couple both mass transport and CaOx precipitation
reaction at the surface of the crystal. It is shown that the crystal growth rate increases with solution supersaturation increasing and decreases with the crystal size increasing. The findings also indicated that in cases of low bulk solution supersaturation and low surface reaction constant values,
the crystal growth rates are controlled by the surface reaction kinetics and independent on the species transport. When the bulk solution supersaturation and surface reaction constant values are high, the Ca and Ox surface concentrations become lower than the bulk solution concentration values. Thus,
the crystal growth rates are controlled by the species transport. The presented study also shows that in the presence of inhibitor osteopontin, the crystal growth rate was decreased.