Starch-coated metal-organic framework for controlled metronidazole delivery: Antibacterial performance and...

Targeting the critical challenge of controlled antibiotic delivery, this study introduces a novel, biocompatible carrier based on starch-coated Metal-organic Frameworks (MOFs), specifically utilizing MIL-100 and MIL-101 to encapsulate metronidazole (MTZ). Comprehensive structural characterization, including FT-IR, PXRD, TGA, BET, and DLS, confirmed the integrity of the MOF scaffolds, high drug loading efficiency, and successful surface functionalization. The starch coating dramatically altered drug release kinetics: MTZ@MIL-100_Starch exhibited a sustained and gradual release profile, a critical feature for prolonged therapeutic action. Molecular simulations provided essential mechanistic insight, clearly defining the host-guest interactions responsible for MTZ retention and controlled release. Biologically, the coated formulation demonstrated significantly enhanced antibacterial efficacy against both Staphylococcus aureus and Escherichia coli. The MTZ@MIL-100_Starch consistently outperformed the uncoated formulation across all parameters (MIC, MBC, and time-kill), requiring a minimal effective dose due to improved particle-cell interactions. While metronidazole served as the primary model drug to optimize the carrier's physicochemical properties and release kinetics, the platform's broad-spectrum antibacterial versatility was further validated by parallel tests using doxycycline, confirming the carrier's ability to enhance the efficacy of diverse antibiotics. Finally, the starch coating conferred superior cytocompatibility across three different human cell lines (HaCaT, HFF, and NIH), confirming its safety profile.