Chapter 17: Manipulation of Interfaces on Vector Materials

We define a vector material as one that can manipulate its surrounding using force irradiating locally and continuously from the material itself. The effect produced by a vector material has unparalleled importance under the circumstance of the limited use of external forces such as in vivo. We have found that hydroxyapatite (HAp) ceramics become electrets via the electric polarization procedure, and the electrets have vector effects, which can manipulate their surrounding constituents. The polarized HAp electrets accelerate and decelerate crystal growth rate in simulated body fluid (SBF), and control the proliferation of microorganism. In addition to our examples, some types of vector materials are found and employed in biomedical applications: bioactive glass and radioactive materials. Bioactive glass solves in aqueous medium, thus, the solubility work on the environment. Radioactive materials irradiate β-rays to and affect cancer cells in the vicinity of the materials. This Chapter also presents the concept of vector effects and reviews the examples of vector materials.