Siyah Titanyum Dioksit Nanoyapıların Elektrokimyasal Metotlar ile Sentezlenmesi ve Antibakteriyel Özelliklerinin Değerlendirilmesi

Abstract

Black titania (titanium dioxide - TiO2) offers superior photocatalytic and antibacterial properties compared to conventional titania, thanks to its reduced bandgap and enhanced light absorption capacity. In this study, the synthesis and detailed characterization of black titania nanotube arrays were performed using an electrochemical reduction method. Titanium surfaces were subjected to anodic oxidation to produce nanotubes with distinct morphologies, followed by cathodic polarization in sodium sulfate electrolytes under various durations and voltages. Characterization studies were conducted using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDS), X-ray diffraction (XRD), Atomic Force Microscopy (AFM), Water Contact Angle (WCA) measurement, surface energy analysis, UV-Vis Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), and Electron Paramagnetic Resonance (EPR). Results showed that cathodic polarization did not significantly alter titania's morphology or crystal structure. Optimal polarization parameters were determined as 5 V and 60 seconds. The bandgap of black titania decreased compared to normal titania, and defects such as Ti3+ ions and oxygen vacancies were detected. Antibacterial activity tests conducted on gram-positive Staphylococcus aureus and gram-negative Escherichia coli under both light and dark conditions revealed that black titania reduced bacterial counts by 55–75% compared to plain titanium foil, although no significant difference was observed compared to normal titania. Cell culture analyses demonstrated that black titania surfaces supported cell adhesion, spreading, and viability. Notably, the nanotube structure produced by 60 V initial anodic oxidation and 20 V secondary anodic oxidation, which exhibited a unique morphology containing Ti3+ ions and oxygen vacancies, holds potential for reducing infection risk and supporting cell adhesion in dental and orthopedic implants.