A bone replaceable artificial bone substitute: Cytotoxicity, cell adhesion, proliferation, and alkaline phosphatase activity

Cellular toxicity, cell adhesion and proliferation, and alkaline phosphatas e (ALP) activity were investigated for an artificial bone substitute compos ed of heated carbonate apatite (CAp) and Type I atelocollagen (AtCol) extra cted from bovine tail skins (88/12 in %wt/wt). To enhance the intramolecula r crosslinking between collagen molecules, the CAp-AtCol substitutes were i rradiated by ultraviolet rays (wave length 254 nm) at 4 degreesC for 4 h or vacuum dried at 150 degreesC for 2 h. Cytotoxicity tests by a direct conta ct method and an extract dilution method revealed that the CAp-AtCol substi tutes were cytocompatible for balb 3T3 fibroblasts. Osteoblast adhesion stu dies demonstrated that the substitute disks composed of 980 degreesC-heated CAp and AtCol were significantly more adhesive for osteoblasts than these of 1200 degreesC-sintered CAp and AtCol (p < 0.05). proliferation studies s howed that the number of osteoblasts grown in the media containing substitu tes of 980<degrees>C-heated CAp and AtCol was statistically higher than gro wn in these of 1,200 degreesC-sintered CAp and AtCol after 5 days (p < 0.05 ). It was found that osteoblasts grown in the substitutes of 980<degrees>C- heated CAp and AtCol only expressed similar ALP activity to the controls. T hese results suggested that the substitutes consisting of 980 degreesC-heat ed CAp and AtCol show more favorable interactions with osteoblasts than tho se of 1,200 degreesC-sintered CAp and AtCol.