Quantifying structural changes in organised biomineralized surfaces using synchrotron Polarisation-Induced Contrast...

Area of Science:

• Biomineralization research
• Materials science
• Biophysics

Background:

• Quantitative characterization of biomineral surfaces is vital for regenerative medicine.
• Existing techniques for surface analysis have limitations, including extensive sample preparation, limited scale, and inability for repeated measurements.

Purpose of the Study:

• To develop Calcium (Ca) K-edge Polarisation Induced Contrast X-ray Fluorescence (PIC-XRF) for quantifying hydroxyapatite (HAp) crystallite structural arrangements.
• To address limitations of current techniques by enabling minimally prepared, repeated surface measurements.
• To analyze structural changes in biomineral surfaces, exemplified by human dental enamel.

Main Methods:

• Utilized Calcium (Ca) K-edge Polarisation Induced Contrast X-ray Fluorescence (PIC-XRF) with a focused monochromatic X-ray source.
• Measured minimally prepared human dental enamel at different rotational angles.
• Quantified crystallite orientations (principal and secondary) and texture in low and high textured surfaces.

Main Results:

• PIC-XRF successfully quantified HAp crystallite orientations and texture in human dental enamel.
• The technique identified crystallites oriented perpendicular to the surface, a challenge for other synchrotron methods.
• Detected significant structural modifications following short-term acid erosion, including shifts in crystallite orientation and reduced surface texture (p < 0.001).

Conclusions:

• PIC-XRF is a powerful tool for quantifying biomineral surface structure with minimal sample preparation.
• The method allows for monitoring of surface structural changes through repeated measurements.
• Findings suggest preferential dissolution of HAp based on crystallite orientation, offering insights for regenerative strategies.