Immobilization of antibacterial copper metal-organic framework containing glutarate and 1,2-bis(4-pyridyl)ethylene ligands on polydimethylsiloxane and its low cytotoxicity

Abstract

Metal-organic frameworks (MOFs) that include bioactive metals may exhibit activity against various microbes through metal–ligand bond cleavage to release metal ions or ligands into the media. However, controlled release over an extended time is required to avoid toxicity due to excess metal ions for successful clinical applications. Recently, copper-based MOFs (Cu-MOFs), which showed sustained release capability, porosity, and structural flexibility, exhibited antibacterial properties. Herein, toward the development of regenerative biomedical applications, we immobilized a robust Cu-MOF containing glutarate and 1,2-bis(4-pyridyl)ethylene ligands within biocompatible polydimethylsiloxane (PDMS) via simple hydrosilylation at 25 °C. The PDMS-immobilized Cu-MOF (PDMS@Cu-MOF) exhibited concentration-dependent antibacterial activities against five bacterial strains: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and methicillin-resistant Staphylococcus aureus. Furthermore, PDMS@Cu-MOF maintained the physical and thermal properties of PDMS and showed low cytotoxicity toward mouse embryonic fibroblasts. Owing to its antibacterial properties and low cytotoxicity, PDMS@Cu-MOF exhibited potential for medicinal applications, such as implants, skin disease treatment, wound healing, and drug delivery.