Electrodeposition of Cu nanoparticles on TiO₂ nanotubes for enhanced bactericidal effect against Escherichia coli

Effective and environmentally friendly disinfection methods are crucial for preventing infections and deaths. In this work, we produced anodic TiO₂ nanotubes (TNTs) composited with copper nanoparticles via electrodeposition. The TNTs were prepared by two-step anodic oxidation, after which Cu nanoparticles were deposited onto them using cyclic voltammetry (CV) for 2, 3, and 5 cycles at scan rates of 20, 50, and 100 mV s^-1. Field emission scanning electron microscopy (FESEM) images revealed that deposition at the highest scan rate (100 mV s^-1) achieved superior nanoparticle dispersion on the TNTs compared to lower rates. Diffuse reflectance spectroscopy (DRS) and Mott-Schottky analysis indicated that the sample prepared with 2 cycles at 100 mV s^-1 exhibited the best photocatalytic activity. For this optimal composite, the band gap and flat band potential were 1.68 eV and -0.579 V, respectively, compared to 3.32 eV and -0.631 V for pristine TNTs. The bactericidal activity of the TNTs and Cu-deposited TNTs was tested against Escherichia coli (E. coli) under visible light irradiation. The composite electrodeposited with 2 cycles at 100 mV s^-1 exhibited bactericidal activity approximately 79.3% higher than that of pristine TNTs under visible light and 28.2% higher in the dark. This study demonstrates a cost-effective and efficient method for fabricating composites with high bactericidal performance for medical and dental applications.