Calcium Oxalate Crystallization: Influence of pH, Energy Input, and Supersaturation Ratio on the Synthesis of Artificial Kidney Stones.

Helen Werner,Sebastian P Schwaminger,Michael Schobesberger,Shalmali Bapat,Doris Segets

doi:10.1021/acsomega.1c03938

Helen Werner, Sebastian P Schwaminger + Show 3 more

Open Access

https://doi.org/10.1021/acsomega.1c03938

Copy DOI

Abstract

The removal of kidney stones can lead to small residual fragments remaining in the human body. Residual stone fragments can act as seeds for kidney stone crystallization and may necessitate another intervention. Therefore, it is important to create a consistent model with a particle size comparable to the range of kidney stone fragments. Thus, the size-determining parameters such as supersaturation ratio, energy input, and pH value are examined. The batch crystallizations were performed with supersaturation ratios between 5.07 and 6.12. The compositions of the dried samples were analyzed with Raman spectroscopy, infrared spectroscopy, and X-ray diffraction (XRD). The samples were identified as calcium oxalate monohydrate with spectroscopic analysis, while calcium oxalate dihydrate being the most prominent crystalline species at all supersaturation ratios for the investigated conditions. The aggregate size, obtained with analytical centrifugation, varied between 2.9 and 4.3 μm, while the crystallite domain size, obtained from XRD, varied from 40 to 61 nm. Our results indicate that particle sizes increase with increasing supersaturation, energy input, and pH. All syntheses yield a high particle heterogeneity and represent an ideal basis for reference materials of small kidney stone fragments. These results will help better understand and control the crystallization of calcium oxalate and the aggregation of such pseudopolymorphs.

Highlights

Calcium oxalate is a mineral of the oxalate group[1] and occurs naturally in humans, in plants, and in various industrial processes.[2−6] In the pulp and paper industry and in the production process of sugar, it is important to suppress the precipitation of calcium oxalate.[4,7]Calcium oxalate can be precipitated in humans and cause the formation of kidney stones in the urogenital tract
Powder samples were analyzed with Raman spectroscopy, attenuated total reflectance (ATR) Fourier transform infrared (FT-IR) spectroscopy, and optical microscopy
We wanted to create standard clinically insignificant residual fragments (CIRFs) to ensure that their composition is independent of the patient’s medical history and that the procedure can be performed with standard laboratory equipment

Summary

Introduction

Calcium oxalate is a mineral of the oxalate group[1] and occurs naturally in humans, in plants, and in various industrial processes.[2−6] In the pulp and paper industry and in the production process of sugar, it is important to suppress the precipitation of calcium oxalate.[4,7]. Calcium oxalate can be precipitated in humans and cause the formation of kidney stones (urolithiasis) in the urogenital tract. Nucleation can be triggered by de novo synthesized fragments (primary nucleation) or fragments present in the solution (secondary nucleation).[14]

Objectives

Methods

Results

Conclusion