Vibrational spectroscopic study of tetracalcium phosphate in pure polycrystalline form and as a constituent of a self-setting bone cement

Abstract

Polycrystalline tetracalcium phosphate (TTCP), a material of considerable interest for human implantation due to its similarity to hydroxyapatite, was studied by means of Raman and FT-IR spectroscopy. The spectra were interpreted on the basis of group theoretical considerations. In addition, the setting reaction of a calcium phosphate cement (CPC) consisting of an equimolar mixture of TTCP and dicalcium phosphate (DCPA) was investigated by Raman spectroscopy. The band of the totally symmetric phosphate mode v1 of TTCP showed marked factor group splittings. The splitting components arose at coincident wave numbers in the IR and Raman spectra. This observation was in accordance with space group P2(1) (factor group C2(2), Z = 4). The characteristic splitting of v1 allowed the setting reaction of CPC to hydroxyapatite to be followed. According to the Raman spectroscopic results, considerable amounts of TTCP must be present at the sample surface after 24 h of setting in an aqueous environment.

Tetracalcium phosphate: Synthesis, properties and biomedical applications

“…Table 2 shows the wave numbers of the measured Raman and IR spectra, which consisted of bands due to lattice vibrations of Ca 2+ and O 2-ions and the vibrational modes of phosphate ions. Theoretical calculations based on factor group symmetry [23] were carried out independently by two groups [22,24] and predicted more bands for space group P2 1 than were actually observed in both studies. The reason for this may be superimposed or hidden bands, or bands with intensities below detection limits.…”

“…Bertoluzza et al [21] presented some IR data for TTCP, but only for comparison purposes and without proper interpretation and assignment of the measured bands. A more complete investigation was carried out by Posset et al [22], who studied TTCP in pure polycrystalline form and as a constituent of a cement setting reaction. Table 2 shows the wave numbers of the measured Raman and IR spectra, which consisted of bands due to lattice vibrations of Ca 2+ and O 2-ions and the vibrational modes of phosphate ions.…”

Self Setting Bone Cement Formulations Based on Egg shell Derived TetraCalcium Phosphate BioCeramics

“…FT-IR spectra of both the pure TTCP and ETTCP (Figure 1b) consists of bands due to the vibration modes of phosphate ions (ν1-ν4) as listed in Table 3. Typically it consist of a broad band around 1005 cm -1 due to ν3 (three fold degenerate stretching mode), weak band arising from ν1 (symmetric stretching mode) between 959 and 942 cm -1 and ν4 threefold degenerate deformational mode giving rise to two sharp isolated band between 620 and 562 cm -1 [31]. The vibration bands of ETTCP were found to be slightly different from pure TTCP bands, due to the substitution of Mg 2+ , Na + , Sr 2+ ions for the Ca 2+ ion in ETTCP sample [6].…”

Properties of Powder Composite Polyhydroxybutyrate–Chitosan-Calcium Phosphate System

“…Note that none bands from the vibration of phosphate group in tetracalcium phosphate (e.g. at dublets at 940, 946 and 955 and 962 cm -1 (ν 1 symmetric stretching mode) and fine splitting of band between 987 and 1133 cm -1 (ν 3 degenerate stretching mode) [27]) so as bending O-P-O(H) vibrations of monetite bonds fully vanished from spectrum. This fact revealed completely transformation of cement components to hydroxyapatite.…”