Harnessing in vitro cytotoxicity and antibacterial potential of a novel silver-DABCO framework against multi-drug-resistant pathogens

Abstract

This study aimed to synthesize and characterize silver-based metal–organic frameworks (Ag-MOFs) using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the organic ligand and to assess their antibacterial and cytotoxic properties. The formation of Ag-MOF-D was confirmed by the appearance of a brown solution and a surface plasmon resonance peak at 394 nm in UV-vis spectroscopy. Fourier-transform infrared spectra showed characteristic peaks at 673, 705, 883, 1060, 1382, 1654, and 3250 cm⁻¹. Powder X-ray diffraction patterns indicated a crystalline structure with peaks at 33°, 38°, 55°, and 66°, with an average particle size of 15.68 nm. Ag-MOF-D displayed thermal stability up to 650 °C with a residual mass of 91.50%. Scanning electron microscopy revealed spherical morphology with minimal aggregation, while energy-dispersive X-ray spectroscopy showed 88.64 wt% Ag⁺. Transmission electron microscopy indicated mono-dispersed spherical particles with an average diameter of 10.47 ± 1.80 nm and a lattice fringe spacing of 0.19 nm. The type II isotherm and Brunauer–Emmett–Teller analysis suggested a mesoporous structure of Ag-MOF-D with a surface area of 5.3005 m² g⁻¹ and an average pore diameter of 9.46 nm. Minimum inhibitory and minimum bactericidal concentration values against multi-drug-resistant bacterial strains ranged from 3.90 to 7.80 μM and 7.8 to 62.5 μM, respectively. In vitro cytotoxicity testing on Vero cell lines indicated a dose-dependent decrease in cell viability, with an IC₅₀ value of 1.701 × 10⁻² mg mL⁻¹. These findings suggest that Ag-MOF-D holds potential for antibacterial applications and biocompatibility, with future opportunities for environmental and food safety applications.