Bioinspired Synthesis of Silver Nanoparticles Using L. Reuteri: Antibacterial Efficacy, Molecular Docking Insights, and Cytotoxicity Assessment

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AbstractThis study reports the green synthesis of silver nanoparticles (AgNps) by using Lactobacillus reuteri. Characterized AgNps exhibited near‐spherical morphology with an average size of 86.54 nm, as revealed by SEM (scanning electron microscopy), TEM (transmission electron microscopy), and AFM (atomic force microscopy) analyses. The nanoparticles displayed a slightly rough surface, with some particles exhibiting surface protrusions and sharp edges. The zeta potential measurement of −30.16 mV and electrophoretic mobility of −2.36 cm2/Vs that indicated the presence of negatively charged functional groups on the AgNps surface, suggesting stabilizing biomolecules that prevent nanoparticle aggregation in solution. The hydrodynamic size of the AgNps was determined to be 140.3 nm, and XRD (X‐ray diffraction) analysis revealed a crystallinity of 76.89% with an average crystal size of 8.35 nm and an interplanar distance of 0.233 nm. AgNps demonstrated crystallinity and potent antibacterial activity against Pseudomonas aeruginosa (92.9% killing efficiency) and an ATCC reference strain (76.8%). Molecular docking revealed moderate interactions between an optimized Ag3 cluster and key amino acid residues (Arg277, Gln279, Trp280, Asp273, and Val276) in the P. aeruginosa protein. These interactions, with binding energies ranging from −1.89 to −3.68 kcal/mol, suggested a potential mechanism for the observed antibacterial activity. A charge transfer interaction involving Asp273, contributing a stabilization energy of 3.66 kcal/mol, was identified as a key factor in the Ag‐protein complex formation.