Hydroxyapatite nanoceramics: Basic physical properties and biointerface modification

A new method of surface energy modification and engineering of the hydroxyapatite (HAp) nanoceramics coatings is presented. It is performed by electron-induced surface energy modification resulting in deep and tunable variation of its wettability state. It is found from electronic traps state spectroscopy studies of the HAp ceramics implemented by various methods such as photoluminescence and surface photovoltage spectroscopy, that the HAp nanoceramics is a wide band gap p-type semiconductor with complex structure of electron/hole bulk and surface localized states. It is shown that a low-energy electron irradiation leads to surface potential modulation and provides tailoring any wettability state in a wide range of contact angles by variation of injected and trapped electron charge. The diverse wettability states engineered on the HAp surface enable selective adhesion of basic biological cells such as proteins, DNA and various bacteria.