Superior antibacterial activity of Fe3O4@copper(ii) metal–organic framework core–shell magnetic microspheres

Abstract

With the rapid evolution of antibiotic resistant bacteria, it has become more and more difficult to treat bacterial infection with traditional antibiotics. Therefore, new strategies with high antibacterial efficiency are urgently needed to combat bacteria effectively. Herein, Fe₃O₄@copper(II) metal–organic framework Cu₃(BTC)₂ (Cu-BTC) core–shell structured magnetic microspheres were prepared via a layer by layer growth process. The as-prepared Fe₃O₄@Cu-BTC possessed a unique broad-spectrum antibacterial potency against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The slowly released copper ions and enhanced reactive oxygen species (ROS) generation by facilitating the effective separation and transfer of photoexcited electron–hole pairs played a role in the antibacterial activity of Fe₃O₄@Cu-BTC. Copper ions released from Fe₃O₄@Cu-BTC adhered to the negatively charged bacterial cell, interacted with the bacterial membrane, destroyed the integrity of the membrane which resulted in leakage of bacterial content and then generated ROS to damage DNA, thus leading to cell death. Accordingly, this study provides a competitive strategy for preparing recyclable antibacterial materials that are endowed with targeted antibacterial therapy.