Early Stages of Biomineral Formation—A Solid-State NMR Investigation of the Mandibles of Minipigs

Abstract

Solid-state nuclear magnetic resonance (NMR) spectroscopy allows for the identification of inorganic species during the biomineral formation, when crystallite particles visible in direct imaging techniques have not yet been formed. The bone blocks surrounding dental implants in minipigs were dissected after the healing periods of two, four, and eight weeks, and newly formed tissues formed around the implants were investigated ex vivo. Two-dimensional 31 P-1 H heteronuclear correlation (HETCOR) spectroscopy is based on the distance-dependent heteronuclear dipolar coupling between phosphate-and hydrogen-containing species and provides sufficient spectral resolution for the identification of different phosphate minerals. The nature of inorganic species present at different mineralization stages has been determined based on the 31 P chemical shift information. After a healing time of two weeks, pre-stages of mineralization with a rather unstructured distribution of structural motives were found. After four weeks, different structures, which can be described as nanocrystals exhibiting a high surface-to-volume ratio were detected. They grew and, after eight weeks, showed chemical structures similar to those of matured bone. In addition to hydroxyapatite, amorphous calcium phosphate, and octacalcium phosphate, observed in a reference sample of mature bone, signatures of ß-tricalcium phosphate and brushite-like structures were determined at the earlier stages of bone healing.

Transformation of Phosphorus in Speciation and Bioavailability During Converting Poultry Litter to Biochar

“…was therefore assigned to poorly crystalline hydroxyapatite (Jaeger et al, 2006;He et al, 2007;Vyalikh et al, 2017). The same peak was also observed for C350 and C400.…”

Intermolecular channels direct crystal orientation in mineralized collagen

“…They subsequently develop into platelets that are embedded between the collagen layers as shown in c. A 3D array of oriented parallel platelets eventually forms, as shown in d. small amounts of amorphous calcium phosphate (ACP) and octacalcium phosphate (OCP). These have been suggested to be precursors to bone mineralization [28][29][30] and can still exist in mature bone 24,31 , but are difficult to identify by LDSAED. Most crystals were intrafibrillar with dimensions of~65 × 20 × 3 nm ( Fig.…”

Intermolecular Channels Direct Crystal Orientation in Mineralized Collagen

“…This implies that the platelets are only uniaxially oriented. 15 No other calcium phosphate phase was detected, although it is possible that the sample still contains small amounts of amorphous calcium phosphate (ACP) and octacalcium phosphate (OCP), which have been suggested to be precursors to bone mineralization 28,29 and can still exist in mature bone, 24,30 but are difficult to identify by LDSAED.…”