Influence of CO2 laser irradiation strategy on titanium surface modification and bacterial biofilm contamination: An in vitro study

Abstract

Background: This study investigates the effects of CO₂ laser surface treatment on grade V commercially pure titanium (CP Ti) to improve its antibacterial properties. It evaluates the impact of this process on the implant’s surface characteristics, including topography, and hydrophilicity.Methods: A total of 22 Grade V CP Ti discs were CNC-machined into 8mm × 3mm, polished, and divided into two groups: Ti/control and Ti/laser (n=11 per group). The Ti/laser samples were subjected to CO₂ laser treatment at a 1064 nm wavelength with a power of 6 watts. Surface properties were examined using a wettability test and atomic force microscopy (AFM). To assess bacterial adhesion, biofilms of S. epidermidis, S. aureus, E. coli, and P. aeruginosa were grown on the titanium surfaces of both groups. Dead bacteria were stained with Propidium Iodide (PI) fluorescent dye, visualized under a fluorescent scanning microscope, and quantified using ImageJ software. The obtained data were analyzed statistically.Results: The mean surface roughness (Ra) of the laser-treated samples was measured at 229.97 nm, which was significantly greater than the 72.09 nm observed in the control group. Contact angle measurements indicated values of 83.19° for Ti/control and 41.39° for Ti/laser, demonstrating a substantial increase in hydrophilicity for the laser-treated surfaces. Fluorescent imaging of dead bacteria revealed a significantly higher count on Ti/laser surfaces (338.18) compared to the control group (6.92) (P < 0.0001*).Conclusion: The CO₂ laser effectively modified CP Ti surfaces, producing nano-textured, hydrophilic surfaces with antibacterial properties. This enhancement reduced biofilm formation.