Electrically Functionalized Hydroxyapatite and Calcium Phospate Surfaces to Enhance Immobilization and Proliferation of Osateoblasts In Vitro and Modulate Osteogenesis In Vivo

Hydroxyapatite (HAP) is used to fabricate implants for bone repair in dentistry and orthopaedics. To functionalise the surface of HAP that is in direct contact with human cells a surface electrical charge deposition has been achieved by means of hydrogenation technology. This technology provides uniform 3 dimensioned processing of the specimen surfaces. The engineered charge was estimated from measurements of the photoelectron emission work function (ϕ). The later was increased to ~ 0.2 eV. The negatively charged HAP surface attached 10 times more osteoblatic cells and increased their proliferation capacity 1.6 times, in contrast to the uncharged one. The above increment of ϕ had an effect on the differentiation of mesenchymal stromal cell pool (MSCP) immobilized on the calcium phosphate (CP) coatings. In vivo experiments (BALB/c mice) demonstrated that hydrogenation of CP coatings could effect MSCP differentiation into fibroblasts or osteoblasts. The technique of intracellular RNA staining detected the actively synthesizing osteoblasts and bone marrow stromal cells