Cytocompatibility of Anodic Oxidized Titanium Doped with Antibacterial Compounds

Objectives: Micro-arc oxidation can produce a porous anatase layer on the titanium implant surface which can absorb more Ca and P ions in biological environment thus enhance the initial cell adhesion and improve the osseointegration. Recent studies focus on developing the surface treatment which would create an anti-bacteria feature on the titanium implant. The aim of this study is to evaluate the cytocompatibility of anodic oxidized titanium doped with antibacterial (Ag⁺, Bi³⁺) compounds. Methods: The antibacterial and bacteriostatic effects of (Ag⁺, Bi³⁺) compounds were tested with Gram-negative Actinobacillus actinomycetemcomitans (A.a.), and Gram-positive streptococcus mutans (S.m.) as the tested bacteria. The titanium discs (12mm in diameter and 1mm in thickness) were anodized under DC280V, 70mA/cm², 25 degree Celsius for 3 minutes. The electrolyte was composed of 0.2M calcium acetate, 0.04Mb-glycerol phosphate disodium (AO), and supperaddition of 0.01M silver nitride (AN), 0.01M bismuth acetate (BA) or bismuth nitride (BN). The samples were cleaned twice with double distilled water, and autoclave sterilized prior to in-vitro test. MG63 human osteosarcoma cells were cultured on the samples for 7 days following by MTT, BCA, and ALP assays. Results: Bismuth compound suspensions have more inhibit effect against Aa and Sm than that of silver nitride. The MG63 cell viability (MTT) is higher on AO, AN, BA, BN than that on the polished samples. The results of BCA assay demonstrate a greatest total protein amount of BN group among others. The alkaline phosphatase activities of MG63 cells are analogous on all test samples. Conclusions: The bismuth doped oxidized titanium which have an anti-bacteria potential will not affect the viability of MG63 osteoblast-like cells. The differentiation ability of MG63 cells cultured on oxidized titanium are not altered by supperaddition of antibacterial (Ag⁺, Bi³⁺) compounds. This research is supported by National Science Council of Taiwan, NSC 98-2221-E-039-004