ULTRAFAST LASER TEXTURING OF TI-6AL-4V SURFACES FOR BIOMEDICAL APPLICATIONS

摘要

By controlling processing parameters such as theaverage fluence, number of laser pulses and beampolarization direction, different types of multiscalesurface textures were produced on Ti-6Al-4Vsurfaces by ultrafast laser processing. The sampleswere textured in ambient atmosphere using an Yb:KYW chirped-pulse-regenerative amplification laserwith a wavelength of 1030 nm and pulse duration of500 fs. The wetting of simulated biological fluids aswell as the human mesenchymal stem cells (hMSCs)behavior were assessed. Three types of texturedsurfaces were tested, consisting of: (i) Laser-InducedPeriodic Surface Structures-LIPSS; (ii) nanopillarslikestructures; and (iii) LIPSS overlapped tomicrocolumns. The laser textured surfaces presenthydrophilic behavior and high affinity for HBSS(Hank’s balanced salt solution). Cell spreading andadhesion strength is reduced by the laser nanotexturesas compared to a polished control surface.Cytoskeleton stretching and stress fibers were clearlyobserved on LIPSS while significant filopodiaformation was verified on nanopillars. There was nocell proliferation on the laser nanotextured surfaces.Ultrafast laser texturing of Ti-6Al-4V surfaces is anefficient technique for increasing surface wettability,and is potentially useful as a technique to control thebehavior of hMSCs by changing the cytoskeletonshape, FAPs distribution and area, and proliferation.