Role of Hyaluronic Acid on the Nucleation Kinetics of Calcium Oxalate Hydrates in Artificial Urine Quantified with Droplet Microfluidics

Role of Hyaluronic Acid on the Nucleation Kinetics of Calcium Oxalate Hydrates in Artificial Urine Quantified with Droplet Microfluidics

Ibis, F. (TU Delft Complex Fluid Processing)
Alhaji Nuhu, M.R. (Student TU Delft)
Penha, Frederico Marques (KTH Royal Institute of Technology)
Yu, T.W. (Student TU Delft)
van der Heijden, A.E.D.M. (TU Delft Complex Fluid Processing)
Kramer, H.J.M. (TU Delft Complex Fluid Processing)
Eral, H.B. (TU Delft Complex Fluid Processing)

2022

The increasing prevalence of urolithiasis in industrialized societies triggered considerable interest in how various species found in urine regulate the nucleation and growth of common kidney stone constituents such as calcium oxalate (CaOx). Yet, the role macromolecules play in kidney stone formation is often overlooked due to their low concentration in urine. In this study, we investigate the nucleation kinetics of CaOx in artificial urine with droplet-based microfluidic induction time measurements at varying concentrations of oxalate and hyaluronic acid (HA), a polysaccharide commonly found in urine. The formation of two pseudo-polymorphic forms of calcium oxalate crystals, calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD), are carefully monitored using polarized light microscopy in induction time experiments. COM and COD nucleated concomitantly in artificial urine yet with distinct kinetics. Our results indicate that higher oxalate concentrations favor the formation of COD, the metastable form, over COM, the most stable form. Moreover, COD is also the fastest nucleating form in droplets under studied conditions. Furthermore, increasing the concentration of HA at fixed calcium and oxalate concentrations favored the nucleation of COM. We observed that in droplets where COM nucleated first, COD was not formed within the experimental time scale. However, in the droplets where COD appeared first, COM crystals were also observed later. We hope our findings shed light on the role macromolecules such as HA plays in dictating the pseudo-polymorphic form of CaOx and guide next generation treatments.

http://resolver.tudelft.nl/uuid:862a5d39-9a7c-4150-ab08-da852e1eb459

https://doi.org/10.1021/acs.cgd.2c00198

1528-7483

Crystal Growth & Design, 22 (6), 3834-3844

Institutional Repository

journal article

© 2022 F. Ibis, M.R. Alhaji Nuhu, Frederico Marques Penha, T.W. Yu, A.E.D.M. van der Heijden, H.J.M. Kramer, H.B. Eral