Low-temperature fabrication of titania layer on 3D-printed 316L stainless steel for enhancing biocompatibility

Petal-like titania layer was obtained on the 3D-printing 316L stainless steel substrate by two-step method at low temperature. Liquid phase deposition (LPD) method was used to prepare the fluorine-containing titania transition layer as step 1, not only improving the binding force with the substrate, but also contributing to the deposition of the second bioactive layer obtained by hydrothermal method in step 2. The samples were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS), X-ray fluorescence (XRF) and static state contact angle. The XRF result indicated that the fluorine could be effectively concealed by Petal-like layer in step 2. And the wettability test showed that the as-treated samples were hydrophilic. Furthermore, the calcium-deficient amorphous calcium phosphate (ACP) layer was induced on the as-treated samples via being soaked in 1.5 times simulated body fluid (1.5SBF) solution within 3 days. Meanwhile, the biocompatibility results showed that the adhesion morphology and the quantity of osteoblasts on the sample treated by two-step method were better than the other sample groups. In a word, this two-step method is expected as a novel approach to improve the biocompatibility of the 3D-printing customized biomedical stainless steel.