Fabrication of nano CuAl₂O₄ spinel for copper stabilization and antibacterial application

With widely reported antibacterial potential, the copper-containing nanoparticles have become attractive antibacterial agents to prohibit the undesirable bacterial adhesion and growth. However, after applying the copper-containing agents in the environment, the potential leaching and bioaccumulation of copper ions may cause severe environmental contamination and irreversible health problems. Therefore, the nano CuAl₂O₄ spinel was fabricated as a novel copper-stabilized antibacterial agent with much minimized copper leachability. Results show the successful fabrication of nano CuAl₂O₄ spinel as well-shaped polyhedral particles with maximum length of ˜100 nm and width of ˜50 nm. The optimal parameters for the synthesis of CuAl₂O₄ include pH value of 11.0, sintering temperature of 1000 °C, dwelling time of 3 h, and the heating rate of 5 °C/min. The leaching test also confirmed the superiority of the nano CuAl₂O₄ in copper stabilization. The beneficial antibacterial activity of the nano CuAl₂O₄ was further testified by an obvious decrease in the amount of Escherichia coli in a medium with addition of the CuAl₂O₄ spinel. Besides the growth mechanisms of the nano-particles, this work has also innovatively demonstrated a strategy to replace the traditional antibacterial agents by a novel, long-lasting nano CuAl₂O₄ with little copper leachability.