Surface Potential Energy between Hydroxyapatite and Bacterium

Abstract

We investigated the effect of surface potential energy on the adhesion of bacteria to hydroxyapatite (HAp) using a theoretical calculation of the surface potential energy with the interaction of electrical double layer forces (Vel) and van der Waals forces (V_A) between HAp, protein-coated HAp and oral bacteria.
      Vmax between the HAp and bacteria with a low zeta potential was smaller than that between HAp and bacteria with a higher one. These results show that oral bacteria can be divided into two groups-those that easily adhere to HAp and those that do not.
      The van der Walls forces between protein-coated HAp and bacteria caused them to repulse one another because the Hamaker constant of protein is smaller than that of water. However, surface potential energy was affected more by Vel. It is easy for bacteria that have a low zeta potential to adhere to protein-coated HAp. On the other hand, it is difficult for bacteria with a high zeta potential to adhere to protein-coated HAp because of electrostatic repulsive forces.
      These results suggest that it may be possible to prevent adhesion of bacteria with a high zeta potential to HAp by changing the surface potential energy between bacteria and HAp.