Wettability Engineering and Bioactivation of Hydroxyapatite Nanoceramics

The major trends in biotechnology and tissue engineering are development of materials with controlled surface substrates. One of the critical factors influencing adhesion of biocells is wettability properties of the biomimetic materials. Hydrophilicity/hydrophobicity of any solid state surface depends on interfacial physical properties which can be varied by topographic nanostructuring, surface chemical modification and external electric field. We report about new method enabling reversible switching or gradual transition of wettability properties of materials by surface potential modulation. The use of low energy electron irradiation allows achieving tunable wettability of the hydroxyapatite in a wide range of contact angles from 10° to 100° with accuracy of ±3°. Tailoring the gradually varied wettability state in the hydroxyapatite nanoceramics enabled the differential binding of various biological cells as well adhesion of various sorts of bacteria demonstrating their selective immobilization.