Crafting Hydroxyapatite-Gelatin Composite for Prosthetic Implant’s Bioactive Layer Using Facile Airbrush Spraying Method

Abstract

Metal bone implants, which are typically used in biomedical applications, are not bioactive; therefore, they need to be coated with bioactive materials to improve their biocompatibility. Herein, we report the feasibility of hydroxyapatite (HA)-gelatin composite as a bioactive layer on stainless steel (SS) 316 L. Various ratios were used to optimize HA-gelatin composition as the biolayer. The homogeneous coverings of the HA-gelatin layer were made using a simple airbrush spray coating technique. In this case, the distance between the airbrush-spray nozzle and the SS316L substrate was used to optimize the formed layer, including controlling the thickness and morphology. The phase and morphological assessments utilizing X-ray diffraction and scanning electron microscopy confirmed that the HA-gelatin layer was successfully formed, and there was no sign that the layer had cracks, as the gelatin could increase the durability of the bioactive layer. The mechanical property characterizations using the pull-off PosiTest AT-M dolly revealed the HA-gelatin layer with a ratio of HA-gelatin of approximately 70:30 (wt%) has a strong adhesive strength of up to 13.17 ± 0.90 MPa. The degradation rate performed by immersing the sample in Simulated Body Fluid (SBF) solution was also less than ∼5%, which is adequate for biomedical applications. We believe that our findings could shed light on the development of an economical approach for obtaining a biocompatible layer coated on metal bone implants.