Porous titanium and silicon-substituted hydroxyapatite biomodification prepared by a biomimetic process: characterization and in vivo evaluation.
Porous titanium with a pore size of 150-600 microm and a porosity of 67% was prepared by fiber sintering. The porous titanium had a complete three-dimensional (3D) interconnected structure and a high yield strength of 100 MPa. Si-substituted hydroxyapatite (Si-HA) was coated on the surface by a biomimetic process to improve the surface bioactivity. X-ray diffraction results showed that Si-HA coating was not well crystallized. New bone tissue was found in the uncoated porous titanium after 2 weeks of implantation and a significant increase (p<0.05) in the bone ingrowth rate (BIR) was found after 4 weeks of implantation, indicating the good osteoconductivity of the porous structure. The HA-coated and Si-HA-coated porous titanium exhibited a significantly higher BIR than the uncoated titanium at all intervals, highlighting the better surface bioactivity and osteoconductivity of the HA- and Si-HA coatings. Also, the Si-HA-coated porous titanium demonstrated a significantly higher BIR than the HA-coated porous titanium, showing that silicon plays an active role in the surface bioactivity. For Si-HA-coated porous titanium, up to 90% pore area was covered by new bone tissue after 4 weeks of implantation in cortical bone. In the bone marrow cavity, the pore spaces were filled with bone marrow, displaying that the interconnected pore structure could provide a channel for body fluid. It was concluded that both the 3D interconnected pore structure and the Si-HA coating contributed to the high BIR.
Zhang
Erlin
E
Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, People's Republic of China. erlin.zhang@imr.ac.cn
Zou
Chunming
C
D000818:Animals; D040761:Biomimetic Materials / Q000138:chemical synthesis*; D032701:Biomimetics / Q000379:methods*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000648:ultrastructure; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D017886:Durapatite / Q000378:metabolism*; D020007:Implants, Experimental; D055595:Mechanical Phenomena; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D016062:Porosity; D011817:Rabbits; D011859:Radiography; D012825:Silicon / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014025:Titanium / Q000378:metabolism*; D014961:X-Ray Diffraction
D020099:Coated Materials, Biocompatible; D017886:Durapatite; D014025:Titanium; D012825:Silicon