Biological and antibacterial properties of plasma sprayed wollastonite/silver coatings

In this work, plasma sprayed wollastonite/silver coatings were prepared to obtain an implant material having excellent bioactivity, cytocompatibility as well as antibacterial property. The surface characteristics of wollastonite/silver coating were investigated by scanning electron microscopy, energy dispersive spectrometer, atomic absorbance spectroscope and x-ray diffraction. The bioactivity was examined by simulated body fluid soaking test. The antibacterial activity against Escherichia coli was examined by bacterial counting method. And the cytocompatibility and in vitro osteotoxicity was evaluated by alamarBlue Assay using MG-63 osteoblasts. The results showed that silver existed in the wollastonite coating homogeneously as silver oxide and metal silver, which ensured a sustained release of silver for 28 days in deionized water. The loaded silver showed strong inhibition against the growth of Escherichia coli, however exhibited no osteotoxicity. Although the wollastonite/silver coating can not induce apatite formation as quickly as the wollastonite coating did in simulated body fluid, it still exhibited good bioactivity. Therefore, the plasma sprayed wollastonite/silver coating is a promising implant material to be applied in surgery, reducing postoperative infections.