Introduction
Kokubo and his colleagues developed an acellular simulated body fluid that has inorganic ion concentrations similar to those of human extracellular fluid, in order to reproduce formation of apatite on bioactive materials in vitro. This fluid can be used for not only evaluation of bioactivity of artificial materials in vitro, but also coating of apatite on various materials under biomimetic conditions. The simulated body fluid is often abbreviated as SBF or Kokubo solution. The ion concentrations of SBF are given on Table I.