Alkali-treated titanium selectively regulating biological behaviors of bacteria, cancer cells and mesenchymal stem cells.

[cholangiocarcinoma]

Many attentions have been paid to the beneficial effect of alkali-treated titanium to bioactivity and osteogenic activity , but few to the other biological effect . In this work , hierarchical micro /nanopore films were prepared on titanium surface by acid etching and alkali treatment and their biological effects on bacteria , cancer cells and mesenchymal stem cells were investigated . Gram -positive Staphylococcus aureus , Gram -negative Escherichia coli , and human cholangiocarcinoma cell line RBE were used to investigate whether alkali-treated titanium can influence behaviors of bacteria and cancer cells . Responses of bone marrow mesenchymal stem cells (BMMSCs ) to alkali-treated titanium were also subsequently investigated . The alkali-treated titanium can potently reduce bacterial adhesion , inhibit RBE and BMMSCs proliferation , while can better promote BMMSCs osteogenesis and angiogenesis than acid-etched titanium . The bacteriostatic ability of the alkali-treated titanium is proposed to result from the joint effect of micro /nanotopography and local pH increase at bacterium /material interface due to the hydrolysis of alkali (earth ) metal titanate salts . The inhibitory action of cell proliferation is thought to be the effect of local pH increase at cell /material interface which causes the alkalosis of cells . This alkalosis model reported in this work will help to understand the biologic behaviors of various cells on alkali-treated titanium surface and design the intended biomedical applications .