Laser processing effects on Ti−45Nb alloy surface, corrosive and biocompatible properties

The Ti−45Nb (wt.%) alloy properties were investigated in relation to its potential biomedical use. Laser surface modification was utilized to improve its performance in biological systems. As a result of the laser treatment, (Ti,Nb)O scale was formed and various morphological features appeared on the alloy surface. The electrochemical behavior of Ti−45Nb alloy in simulated body conditions was evaluated and showed that the alloy was highly resistant to corrosion deterioration regardless of additional laser surface modification treatment. Nevertheless, the improved corrosion resistance after laser treatment was evident (the corrosion current density of the alloy before laser irradiation was 2.84×10⁻⁸ A/cm², while that after laser treatment with 5 mJ was 0.65×10⁻⁸ A/cm²) and ascribed to the rapid formation of a complex and passivating bi-modal surface oxide layer. Alloy cytotoxicity and effects of the Ti−45Nb alloy laser surface modification on the MRC-5 cell viability, morphology, and proliferation were also investigated. The Ti−45Nb alloy showed no cytotoxic effect. Moreover, cells showed improved viability and adherence to the alloy surface after the laser irradiation treatment. The highest average cell viability of 115.37% was attained for the alloy laser-irradiated with 15 mJ. Results showed that the laser surface modification can be successfully utilized to significantly improve alloy performance in a biological environment.