The quest for the development of bone substitutes with contrast agents for diagnostic imaging subsists to distinguish synthetic bone from native human tissue. To this aim, ytterbium (Yb3+) substitutions in β-tricalcium phosphate (β-Ca3(PO4)2, β-TCP) as contrast agents has been developed to differentiate implant materials thereby, facilitating as host for bimodal imaging application by means of NIR luminescence and X-ray computed tomography techniques. A facile aqueous chemical precipitation route with the aid of surfactant is used for the synthesis of Yb3+ substitutions in β-Ca3(PO4)2. The characterization results affirms the ability of β-Ca3(PO4)2 to host 4.36 mol% of Yb3+ while the excess Yb3+ crystallizes as YbPO4. The structure refinement results favour the occupancy of Yb3+ at the Ca2+(5) site of β-Ca3(PO4)2. The absorption and photoluminescence spectra in the near infrared region with emission intensity ~1024 nm in the second biological window correspond to 2F5/2 → 2F7/2 transitions of Yb3+. The designed Yb3+ substituted β-Ca3(PO4)2 does not exhibit any toxicity in human osteosarcoma cell lines and delivers an excellent in vitro CT contrast ability allied by the enhanced signal intensity and high X-ray absorption coefficient.
Keywords: Computed tomography; Luminescence; Substitutions; Ytterbium; β-Ca(3)(PO(4))(2).
Copyright © 2018 Elsevier B.V. All rights reserved.