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theses

Calcium oxalate crystallization is widely studied due to the prevalence of this substance in various biomineralization processes, especially the formation of kidney stones. Bulk crystallization studies are a common and popular method for investigating calcium oxalate in particular. Crystallization studies using microfluidic platforms are becoming more popular because of the simplicity of use, cost effectiveness and enhanced control of system variables that these systems offer. Microfluidic systems using a two-input, one-output design results in crystallization at the entrance of the microchannel. This could lead to clogging of the device, and clogging makes it difficult to study crystallization over long lengths of time using these devices. In this study a three-input, three-output microfluidic channel system was designed and a protocol was established that minimized bubble occurrence and synthesized calcium oxalate crystals within the device; crystals were analyzed ex-situ. Equimolar input salt concentrations (CaCl2, K2C2O4) of 20, 40 and 60 mM were used in these experiments. Evidence of crystallization within the device was a line forming in the center channel that grew (i.e., darkened) over time. As the concentration of input salt solution increased, the time that it took for the line to be visible decreased but the length and darkness of the line increased. In order to re-use devices hydrochloric acid was tested as a cleaning solvent, and it proved to be an appropriate solvent that did not alter the crystallization process. Experiments in which sodium polyacrylate (a common additive in calcium oxalate crystallization experiments) was added to the system showed that the additive inhibited the growth of crystals formed within the microfluidic device. Analysis of collected crystals was done by optical and scanning electron microscopy.

ETD_8931

M.S.

Includes bibliographical references

by Jinnie Anstice

doi:10.7282/T3HD800X

ETD graduate

The author owns the copyright to this work.