Enhanced Antimicrobial Activity of Laser-Induced Graphene-Wrapped Trimetal Organic Framework Nanocomposites

Crystalline and porous metal–organic frameworks (MOFs) are potential candidates for different antibacterial, photocatalytic, and adsorption applications. Moreover, multiprincipal element nanoparticles are effective against multidrug-resistant bacteria, and combining metals with carbon nanomaterials can enhance activity. Herein, a Tri-MOF comprised of iron, zinc, cobalt and 2-methyl imidazole is grown together with laser-induced graphene (LIG) powder. Electron microscopy imaging shows the successful preparation and the crystalline nature of the LIG/Tri-MOF composite. Fourier-transform infrared and X-Ray photoelectron spectroscopy confirm a noncovalent mixture of LIG and Tri-MOF. Compared with the negligible activity of LIG alone, low doses (0.91–4.54 mg mL⁻¹) of the prepared LIG/Tri-MOF composite show excellent antibacterial activity (≥95% bacterial removal) and a MIC of 0.6 mg mL⁻¹ for Gram-negative bacteria, via the gradual leaching of metal ions and organic linker from the material enhanced by bacterial aggregation near the LIG/Tri-MOF. Compared to a mixture of separately synthesized Tri-MOF and LIG, the LIG/Tri-MOF composite shows improved antibacterial effects. All materials show cytotoxicity for L929 mouse cell lines, the solids showing a disrupting effect on cells grown in vitro. Performance-enhancing combinations of various materials leading to synergistic or additive antimicrobial effects are essential strategies for minimizing the possible emergence of antibiotic-resistant strains.