Polarization of Femtosecond Laser for Titanium Alloy Nanopatterning Influences Osteoblastic Differentiation

Abstract

Ultrashort pulse lasers have significant advantages over conventional continuous wave and long pulse lasers for the texturing of metallic surfaces, especially for nanoscale surface structure patterning. Furthermore, ultrafast laser beam polarization allows for the precise control of the spatial alignment of nanotextures imprinted on titanium-based implant surfaces. In this article, we report the biological effect of beam polarization on human mesenchymal stem cell differentiation. We created, on polished titanium-6aluminum-4vanadium (Ti-6Al-4V) plates, a laser-induced periodic surface structure (LIPSS) using linear or azimuthal polarization of infrared beams to generate linear or radial LIPSS, respectively. The main difference between the two surfaces was the microstructural anisotropy of the linear LIPSS and the isotropy of the radial LIPSS. At 7 d post seeding, cells on the radial LIPSS surface showed the highest extracellular fibronectin production. At 14 days, qRT-PCR showed on the same surface an increase in osteogenesis-related genes, such as alkaline phosphatase and osterix. At 21 d, mineralization clusters indicative of final osteoinduction were more abundant on the radial LIPSS. Taken together, we identified that creating more isotropic than linear surfaces enhances cell differentiation, resulting in an improved osseointegration. Thus, the fine tuning of ultrashort pulse lasers may be a promising new route for the functionalization of medical implants.

Femtosecond Laser Micro-/Nano-Texturing to Die Substrates for Fine Imprinting to Products

“…In addition to this high intensity power deposition effect to ablation process, the polarization effect on the texturing is taken into account. After [30][31][32], the surface structuring in sub-mm range is significantly affected by the twisted laser beam through the polarization. The straight microgroove textures are formed and aligned under a selected polarization condition, while the nano-islands are formed and aligned under another condition.…”

Nondestructive inspection of surface nanostructuring using label-free optical super-resolution imaging

“…Laser ultra-high precision processing of materials has been widely known for more than five decades. More specifically, the generation of Laser-Induced Periodic Structures (LIPSS or ripples) is a universal phenomenon paving the way for numerous applications 1 , such as tuning the wettability of surfaces 2,3 , adding anti-bacterial functionalities 2,4 , or controlling cell adhesion [5][6][7][8] . Femtosecond lasers can generate LIPSS on surfaces with a periodicity that depends on the irradiation wavelength.…”

Nanopatterning of Bionic Materials

“…Herein, only original research articles have been considered for publication. The present Special Issue includes contributions on the following research topics: Functionalization of Ti-based medical implants by means of laser-induced micro- and nanostructures for cell repellence as well as for osteoblastic proliferation and differentiation [ 2 , 3 , 4 ]; Polymer surfaces with antimicrobiotic and antiadhesive properties induced by laser-induced periodic surface structures (LIPSS) in connection with nanofibers or nanowires [ 5 , 6 , 7 ]; The generation of novel hybrid carbon nanotube materials for biosensing applications by means of laser-induced forward transfer (LIFT) [ 8 ]. …”

“…Functionalization of Ti-based medical implants by means of laser-induced micro- and nanostructures for cell repellence as well as for osteoblastic proliferation and differentiation [ 2 , 3 , 4 ];…”