Tannic acid-iron stabilized probiotic silver nano hybrids: Multi-target gut microbiota modulation and intestinal...

The limited efficacy and adverse effect profile of current pharmacological treatments for intestinal inflammation underscore the need for modalities that preserve gut microbiota balance while attenuating inflammation. The aim of this study was to develop and evaluate a BL@TA-Fe^III@AgNPs system with a view to provide synergistic efficacy against intestinal injury. This research introduces an innovative hybrid bio nanocomposite, BL@TA-Fe^III@AgNPs, comprising viable Bacillus licheniformis coated with a tannic-acid/Fe^III coordination layer that nucleates and anchors 7 ± 1.5 nm silver nanoparticles. Characterization of this composite material was performed using TEM, EDS, XRD, and XPS. Functional assays included probiotic viability, tolerance to simulated gastric and intestinal fluids, and bactericidal activity against Escherichia coli and Staphylococcus aureus. In-depth safety evaluations were carried out using both cell cultures and a mouse model. Therapeutic effects in an acute LPS-endotoxemia mouse model were analyzed by 16S rRNA gene amplicon sequencing and untargeted LC-MS/MS metabolomics of cecal contents. Characterization confirmed structural integrity, colloidal stability in physiological media, and low cytotoxicity (IC₅₀ > 100 μg Ag mL^-1). BL@TA-Fe^III@AgNPs restored transepithelial electrical resistance, lowered malondialdehyde levels, and reshaped microbiota composition and metabolite networks relative to LPS controls. Restoration of the Firmicutes: Bacteroidetes ratio and elevated short chain fatty acid concentrations support BL@TA-Fe^III@AgNPs as a promising adjunctive strategy for acute endotoxin-induced intestinal injury.