title: Immobilization of calcium and phosphate ions improves the osteoconductivity of titanium implants.
abstract: In this work, to elevate weak osteoconductivity of titanium (Ti) implant, we prepared a Ti implant having both calcium and phosphate ions on its surface. To modify calcium and phosphate ions onto Ti, phosphate ions were first immobilized by treating the Ti with a NaH2PO4 solution, followed by CaCl2 treatment to immobilize calcium ions, which created the calcium and phosphate ions-modified Ti (Ca-P-Ti). X-ray photoelectron spectroscopy and thin-layer X-ray diffraction measurement confirmed that both phosphate and calcium ions were co-immobilized onto the Ti surface on the molecular level. Three-hour after seeding MC3T3-E1 murine pre-osteoblast cells on substrates, cell number on Ca-P-Ti was much larger than that of Ti and phosphate-modified Ti (P-Ti), but was similar to that of calcium-modified Ti (Ca-Ti). Also, MC3T3-E1 cells on Ca-P-Ti expressed larger amount of vinculin, a focal adhesion protein, than those on other substrates, probably resulting in larger cell size as well as greater cell proliferation on Ca-P-Ti than those on other substrates. Alkaline phosphatase activity of cells on Ca-P-Ti was greater than those on Ti and P-Ti, but was almost comparable to that of Ca-Ti. Moreover, the largest amount of bone-like nodule formation was observed on Ca-P-Ti. These results provide evidence that calcium and phosphate ions-co-immobilization onto Ti increased the osteoconductivity of Ti by stimulating the responses of pre-osteoblast cells. This simple modification would be promising technique for bone tissue implant including dental and orthopedic implants.
authors: Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors: Sunarso
authors: Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 Japan. Electronic address: toita-r@aist.go.jp.
authors: Riki
authors: R
authors: Toita
authors: Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors: Kanji
authors: K
authors: Tsuru
authors: Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors: Kunio
authors: K
authors: Ishikawa
mesh_terms: D000818:Animals; D002118:Calcium / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D051379:Mice; D010006:Osteoblasts / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects*; D010710:Phosphates / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D014025:Titanium / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D020099:Coated Materials, Biocompatible; D010710:Phosphates; D014025:Titanium; D002118:Calcium
keywords: Calcium ions; Osteoconductive surface; Phosphate ions; Titanium implant