Development of a Highly Proliferated Bilayer Coating on 316L Stainless Steel Implants.

In this research, a bilayer coating has been applied on the surface of 316 L stainless steel (316LSS) to provide highly proliferated metallic implants for bone regeneration. The first layer was prepared using electrophoretic deposition of graphene oxide (GO), while the top layer was coated utilizing electrospinning of poly (ε-caprolactone) (PCL)/gelatin (Ge)/forsterite solutions. The morphology, porosity, wettability, biodegradability, bioactivity, cell attachment and cell viability of the prepared coatings were evaluated. The Field Emission Scanning Electron Microscopy (FESEM) results revealed the formation of uniform, continuous, and bead-free nanofibers. The Energy Dispersive X-ray (EDS) results confirmed well-distributed forsterite nanoparticles in the structure of the top coating. The porosity of the electrospun nanofibers was found to be above 70%. The water contact angle measurements indicated an improvement in the wettability of the coating by increasing the amount of nanoparticles. Furthermore, the electrospun nanofibers containing 1 and 3 wt.% of forsterite nanoparticles showed significant bioactivity after soaking in the simulated body fluid (SBF) solution for 21 days. In addition, to investigate the in vitro analysis, the MG-63 cells were cultured on the PCL/Ge/forsterite and GO-PCL/Ge/forsterite coatings. The results confirmed an excellent cell adhesion along with considerable cell growth and proliferation. It should be also noted that the existence of the forsterite nanoparticles and the GO layer substantially enhanced the cell proliferation of the coatings.