Picosecond laser surface modification of aluminum oxide with fish-scale structures for cell culture

The surface modification of a layer substrate has received attention for many biomedical applications (e.g., tissue engineering and biosensing). Under an in situ control, we proposed a strategy for surface modification of hard and brittle ceramics with ultrafast laser pulses for cell culture. A type of ultrafast laser based on the picosecond pulse technique was employed to ablate the surface of a pristine aluminum oxide (Al₂O₃) substrate. The surface of the formed reproducible micro-nanostructures indicated the fish-scale structures, which was analyzed under different laser ablation conditions. Subsequently, the SV40 T-antigen human embryonic kidney 293 (HEK293T) cells were cultured on the laser-ablated Al₂O₃ substrates. These microstructures and nanostructures can enhance cell proliferation response. The surface effect played a crucial role, by which the surface roughness (R_a) and contact angle (CA) of water droplets on the ablated Al₂O₃ substrate increased with the increasing laser fluence. The formed fish-scale structures were formed by the parameters of laser ablation where the structural characteristics of the Al₂O₃ substrate can be remained in the ultrafast laser process. The presented process provides a simple support for developing ablated structures on the Al₂O₃ substrate for cell culture.