The formation of an antibacterial agent–apatite composite coating on a polymer surface using a metastable calcium phosphate solution

Abstract

A percutaneous device with antibacterial activity and good biocompatibility is desired for clinical applications. Three types of antibacterial agent: lactoferrin (LF), tetracycline (TC), and gatifloxacin (GFLX) were immobilized on the surface of an ethylene-vinyl alcohol copolymer (EVOH) using a liquid phase coating process. In this process, an EVOH plate was alternately dipped in calcium and phosphate ion solutions, and then immersed in a metastable calcium phosphate solution supplemented with 4, 40, or 400 μg/mL of the antibacterial agent. As a result, the antibacterial agent was immobilized on the EVOH surface in the form of an antibacterial agent–apatite composite layer. The amount of immobilized antibacterial agent increased with increasing absorption affinity for apatite in the order: GFLX<TC<LF. On the other hand, the release rate of the antibacterial agent from the composite was ordered in the opposite sense; i.e., LF<TC<GFLX. The composites investigated in this study showed antibacterial activity against Escherichia coli and Staphylococcus aureus, and would be useful as materials in percutaneous devices having antibacterial activity and good biocompatibility.