Effect of surface modification by femtosecond laser on zirconia based ceramics for screening of cell-surface interaction

Abstract

Reconstruction of dental tissue defects is a major challenge facing dentistry. Temporary “platforms” materials for seeding different types of cells and their adhesion and proliferation has been extensively researched. Composites comprising zirconia and natural polymers are used as biomaterials as they meet the requirements for successful platforms for dental tissue repair. The fabrication of defined patterns, smaller than 100 µm, is difficult due to the brittleness of ceramic materials. In the recent years femtosecond laser microprocessing have been applied to modify surface of medical implants. In this study we have demonstrated surface texturing of chitosan, chitosan/ ceramics blends and bulk ceramic from Alumina toughened Zirconia (ATZ) with 150 fs and 400 fs laser pulses at 800 nm and 1040 nm wavelength. A comparative experimental study was performed to evaluate different modes of processing of biopolymer/ceramic material. The results obtained from biopolymers, biopolymer/ceramic composites, ATZ bulk ceramic demonstrate selectively structured morphologies with outstanding topographical properties. Furthermore, the formation of a laser induced microstructures, on all the examined specimens, demonstrate tunability, which strongly depends from the variation of scanning velocity, overlap percentage and laser fluence. Using femtosecond laser pulses, surface structures <100 µm were established on bio -polymer/ceramic surfaces. The microstructured scaffolds were investigated by SEM, EDX, AFM, XRD analyses. The X-ray diffraction analysis demonstrated preservation of the tetragonal phase of Zr ceramics for a specific fs laser treatment conditions namely N < 5. The AFM results showed that femtosecond laser processing influence the surface roughness (Sa), by altering the depth of the structures which is related to the scanning velocity. In this paper, we found a method for optimization of Sa parameter, by increasing the scanning velocity and obtaining an Sa values in the nanometer range, simultaneously keeping the surface integrity of zirconia ceramic. The acquired experimental results demonstrate a path to optimize surface properties which affects cell–material interaction.