Titanium coating: introducing an antibacterial and bioactive chitosan-alginate film on titanium by spin coating

Coating of titanium (Ti) implants with biocompatible polymers were performed to improve bone healing. In this study, pure Ti implants were coated via chitosan and alginate by spin coating method at 1000, 4000, and 8000 rpm. The coating layer was cross-linked by calcium chloride. Their chemical structures were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) evaluations. The morphology of the created coating was observed by scanning electron microscopy (SEM), and the best uniformity was observed in the prepared coating at 8000 rpm (6093× g) spinal speed. The adhesion strength of the coating layer on the substrate was evaluated by the adhesion pull-off test. Also, the best adhesion strength was achieved at an 8000 rpm (6093× g) coating rate. Bioactivity of the chitosan-alginate coating on Ti sheets was evaluated by soaking the samples in a simulated body fluid (SBF) solution. The apatite formation on prepared Ti sheets was investigated by SEM, XRD, and energy dispersive X-ray spectroscopy (EDS). A higher mineralization appeared on coated samples compared with pure Ti. The antibacterial behavior of the implants was analyzed by bacterial counting against Escherichia coli. The presence of chitosan and alginate on the Ti sheets resulted in a better antibacterial effect. In-vitro experiments, with L929 fibroblast cells, confirmed the biocompatibility of the implants. Coating the Ti implants with chitosan and alginate improved biomineralization and biological behavior of the implant especially at the spinal speed of 8000 rpm (6093× g). These implants can support osteoblast cell adhesion and facilitate bone regeneration.