title: Synthesis, structure, thermal stability, mechanical and antibacterial behaviour of lanthanum (La³⁺) substitutions in β-tricalciumphosphate.
abstract: Five different concentrations of lanthanum (La(3+)) substituted β-tricalcium phosphate [β-TCP, β-Ca3(PO4)2] were formed through aqueous precipitation technique and the results were compared with stoichiometric β-TCP. All the La(3+) substituted β-TCP powders were characterized using XRD, FT-IR, XRF, Raman spectroscopy and Rietveld refinement of the XRD data. The results from the investigation confirmed the presence of La(3+) in rhombohedral β-TCP structure. The substitution of higher sized of La(3+) led to the considerable enhancement in lattice parameters of β-TCP crystal structure and La(3+) was found to have occupied the eight fold coordinated Ca (3) site of β-TCP structure. La(3+) occupancy at the Ca (3) site resulted in the significant distortions of the associated PO4 tetrahedra, which were supported by the Raman and FT-IR spectroscopic techniques. La(3+) presence in the crystal lattice of β-TCP also led to the delay in allotropic phase transformation of β-TCP to α-TCP till 1300°C, thus signifying the good thermal stability of La(3+) substituted β-TCP powders. The antibacterial efficiency of La(3+) substituted β-TCP powders was confirmed from the in vitro tests done on microbes such as Staphylococcus aureus and Escheria coli. Further, the presence of La(3+) in the crystal lattice of β-TCP did not affect the hardness and Young's modulus values of β-TCP.
authors.affiliation: Centre for Nanoscience and Technology, Pondicherry University, Puducherry 605 014, India.
authors.forename: Rugmani
authors.initials: R
authors.lastname: Meenambal
authors.affiliation: Centre for Nanoscience and Technology, Pondicherry University, Puducherry 605 014, India.
authors.forename: Ram Kishore
authors.initials: RK
authors.lastname: Singh
authors.affiliation: Centre for Nanoscience and Technology, Pondicherry University, Puducherry 605 014, India.
authors.forename: P
authors.initials: P
authors.lastname: Nandha Kumar
authors.affiliation: Centre for Nanoscience and Technology, Pondicherry University, Puducherry 605 014, India. Electronic address: para_kanna@yahoo.com.
authors.forename: S
authors.initials: S
authors.lastname: Kannan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000737:chemistry* / Q000494:pharmacology; D006358:Hot Temperature; D007811:Lanthanum / Q000737:chemistry* / Q000494:pharmacology; D011208:Powders; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D002130:Calcium Phosphates; D011208:Powders; C485817:beta-tricalcium phosphate; D007811:Lanthanum
keywords: Antibacterial; Lanthanum; Mechanical; Thermal stability; β-Ca(3)(PO(4))(2)