Antibacterial and anti-adhesive zeolite coatings on titanium alloy surface

To reduce the incidence of peri-implant infections, zeolite coatings on titanium alloy surface have been prepared and their antibacterial as well as anti-adhesive properties were studied. Continuous zeolite A thin films of 1-4 μm thickness were coated onto titanium alloy surface through in situ crystallization method under hydrothermal conditions. Small amount of silver ions (ca. 2 wt.%) was incorporated into the zeolite layer by an ion-exchange process to provide antibacterial activity. X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), contact angle measurement and scratch test were employed to characterize the coating surfaces. The antibacterial activity of silver incorporated zeolite coatings against methicillin-resistant Staphylococcus aureus (MRSA) evaluated in vitro showed that bacterial proliferation was significantly inhibited both in the culture medium surrounding the material and on the material surface. Moreover, the superhydrophilic nature of zeolite coating provides additional anti-adhesive property to the material surface. The results of in vitro cytotoxic assessment showed that both the zeolite coatings and silver-containing zeolite coatings have good biocompatibility. The antibacterial and anti-adhesive zeolite coatings will have potential application in orthopedic implants.