Concept and development of vector ceramics for bio-interface engineering

Abstract

A vector material is defined as the one to manipulate surrounding inorganic and organic compounds, microorganisms, and tissues using a force irradiated locally and continuously from the material itself. The effect given by a vector material is ca materials are of unparalleled importance under the circumstance of the limited use of external forces such as in vivo. We have recently experimentally demonstrated the effectiveness of electrically polarized hydroxyapatite (HA) electrets as vector ceramics, which can independently irradiate an electrostatic force to the surrounding constituents; crystal growth from a simulated body fluid was accelerated or decelerated and proliferation of a microorganism was controlled on the surfaces of polarized HA, depending upon the electric signs of surface charges. Prior to our study, certain types of vector effects have already been employed in biomedical applications; the so-called 45S5-type bioactive glass (Bioglass®), developed by Hench et al., has long been recognized to be bioactive because of its solubility in a aqueous medium. Radioactive ceramics irradiate β-ray to and work on surrounding cancer cells. These are also vector materials. In addition to these examples, various kinds of vector effects and ceramics are now under development. This advanced report presents the concept of vector effects and reviews the examples of vector ceramics.