Many fundamental mechanisms of the biomineralization processes (bone, teeth etc.) are not clearly understood nowadays. This is partly due to the analytical challenge of simultaneously characterizing the three-dimensional (3D) structure and chemical composition of these materials at the nanometer scale, which can, in principle be achieved by atom probe tomography (APT).

Atom probe tomography (APT) is a relatively new technique for the analysis of bones, teeth or biominerals structures in general. APT can characterize the microstructure of materials in 3D down to the near-atomic level, combined with a high elemental sensitivity, down to parts per million (ppm) across the entire periodic table [1]. APT application to study biomineralization phenomena is plagued by low sample yield and poorer analytical performance compared to metals [2]. Yet, the hierarchical structures of biominerals represent a critical hurdle for APT analysis in terms of yield and analytical resolution, particularly for trace elements, and organic components appear to systematically get lost from the analysis. Here, we applied in-situ metallic coating of APT specimens within the focused ion beam used for preparing specimens and demonstrate that the yield and chemical sensitivity are tremendously improved.

Our results open new possibilities for understanding the hierarchical structure and chemical heterogeneity of biomineral structures at the atomic level and demonstrate the potential of this new method to provide new, unexplored insights into biomineralization processes in the future.

References

[1] Baptiste, Gault et al. "Atom probe tomography." Nature Reviews Methods Primers (2021), 1.1, 51

[2] Kathryn, Grandfield et al. "Atom probe tomography for biomaterials and biomineralization." Acta Biomaterialia (2022), 148, 44-60.

[3] Tim M., Schwarz et al. „Advancing atom probe tomography capability for neat-atomic scale understanding of bone microstructures”, Acta Biomaterialia (2024), under review