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

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 microg/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.