Vibrational spectral fingerprinting for chemical recognition of biominerals

• Published in: Chemphyschem Vol. 21; no. 8; pp. 770 - 778
• Main Authors: Calzolari, Arrigo, Pavan, Barbara, Curtarolo, Stefano, Buongiorno Nardelli, Marco, Fornari, Marco
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 20.04.2020
• Subjects: Apatite; Apatites; Apatites - chemistry; Biocompatible Materials - chemistry; Biomedical materials; biominerals; Carbonation; density functional calculations; Fingerprinting; First principles; Fluorapatite; IR spectroscopy; Models, Molecular; NMR; Nuclear magnetic resonance; Osteoporosis; Spectrum Analysis, Raman; vibrational markers; Vibrational spectra; biominerals; density functional calculations; vibrational markers; Apatites; IR spectroscopy
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.202000016

Pathologies associated with calcified tissue, such as osteoporosis, demand in vivo and/or in situ spectroscopic analysis to assess the role of chemical substitutions in the inorganic component. High energy X‐ray or NMR spectroscopies are impractical or damaging in biomedical conditions. Low energy spectroscopies, such as IR and Raman techniques, are often the best alternative. In apatite biominerals, the vibrational signatures of the phosphate group are generally used as fingerprint of the materials although they provide only limited information. Here, we have used first principles calculations to unravel the complexity of the complete vibrational spectra of apatites. We determined the spectroscopic features of all the phonon modes of fluoroapatite, hydroxy‐apatite, and carbonated fluoroapatite beyond the analysis of the phosphate groups, focusing on the effect of local corrections induced by the crystalline environment and the specific mineral composition. This provides a clear and unique reference to discriminate structural and chemical variations in biominerals, opening the way to a widespread application of non‐invasive spectroscopies for in vivo diagnostics, and biomedical analysis. The impact of bone diseases on the aging population is enormous. Osteoporosis is responsible of 8.9 million fractures annually worldwide. The understanding atomic modifications occurring in calcified tissues is critical to answer fundamental questions regarding the interplay between chemical composition, structure, and biofunctionalities as well as to develop medical solutions at limited costs. Here, we use quantum mechanical calculations to provide experimentalists with the complete spectral features of chemically modified complex phosphate bio‐minerals.