Investigation of ultrafast laser surface patterning and nanocrystalline formation on CrTiN alloy films for enhanced cell proliferation

Titanium (Ti)-based alloys are eye-catching biomaterials extensively utilized in human implants due to their outstanding ability to facilitate cell growth. This research aims to propose a new approach to explore the ultrafast laser processing on alloy surfaces for achieving and regulating the proliferation of biological cells. The study is to directly use the polarization of ultrafast laser irradiation on the surface of chromium-titanium nitride (CrTiN) thin film to fabricate the periodic structures, which can promote cell proliferation. This improvement is accomplished by employing surface patterning and creating nanocrystalline structures. The nanocrystalline layer is treated with laser-induced periodic surface structures (LIPSS), forming subwavelength ripples directly on the surface. The ripples are preferentially formed perpendicular to the direction of laser polarization by controlling the fluence. Through the straightforward technique of ultrafast laser treatment, the wettability transition is contributed to by the combination of LIPSS and modified surface chemistry. It is indicated by the findings that the laser-irradiated CrTiN alloy film exhibits surface ripples and a nanocrystalline phase. This work has the potential to enhance cell proliferation for biomedical engineering applications.