Evidence for aggregation in oxalate stone formation: atomic force and low voltage scanning electron microscopy

Area of Science:

• Mineralogy
• Biomineralization
• Materials Science

Background:

• Oxalate stones are a common type of kidney stone.
• Understanding their formation is crucial for developing prevention and treatment strategies.
• Previous studies suggested crystal growth as the primary mechanism.

Purpose of the Study:

• To differentiate between aggregation and crystal growth in oxalate stone formation.
• To investigate the structure of oxalate stones at high spatial resolution.
• To utilize advanced microscopy techniques for detailed structural analysis.

Main Methods:

• Human oxalate stones and fragments were examined using ultramicrotomy.
• Low voltage scanning electron microscopy (LVSEM) was employed.
• Atomic force microscopy (AFM) was utilized for high-resolution imaging.

Main Results:

• LVSEM revealed lamellar structures up to 10 microns, composed of smaller particles.
• AFM clearly visualized arrays of these smaller particles.
• Particle sizes ranged from 500 to 2800 Angstroms.

Conclusions:

• The findings suggest that oxalate stone formation is driven by ordered aggregation of small crystallites.
• This challenges the sole emphasis on crystal growth as the formation mechanism.
• The study provides new insights into the microstructural basis of oxalate nephrolithiasis.