Tailoring metallurgical and biological characteristics of Ti–6Al–4V alloy by synergetic application of Nd:YAG laser and drug-loaded electrospun PVA

Abstract

Titanium alloys have been used extensively as implants. However, they generally suffer from low biocompatibility as well as antibacterial activity. To date, several strategies have been proposed to address these issues. It is of practical interest to synergistically increase both cellular adhesion and antimicrobial activity in titanium-based implants. Here, Ti–6Al–4V alloys were surface-modified by Nd:YAG laser with different scanning speeds ranging from 1 to 5 mm s−1 and subsequently coated by drug-loaded polymer nanofibers for prolonged drug release. The laser-modified samples were both physically and metallurgically characterized through XRD, OM, AFM, FESEM, hardness, and wettability tests to find the optimum laser processing conditions. Results showed that the surface characteristics of the alloys are sensitive to the scanning speed; the higher the scan velocity, the lower surface roughness and wettability were obtained. The enhanced formation of TiO and Ti6O oxides on the surfaces of laser-modified alloys was delineated. Then, a model polymer/drug system of polyvinyl alcohol/vancomycin was directly electrospun onto the optimized samples surfaces. The laser-modified, drug-loaded samples present an improved biocompatibility as the cellular adhesion and viability were increased in contact with these samples. Up to 39% increase in cell viability was obtained for the laser-modified samples by 5 mm s−1 scan speed in comparison with unmodified, uncoated samples. The increased biocompatibility was attributed to the formation of oxide layers which reduce the toxicity of vanadium and aluminum elements. Also, the drug release rate was extended from 4 h to 25 h for modified samples. So, the modified implants could present a sustained release of antibiotics as well.