The effect of SLP-doped AgNP colloidal biohybrid solution on characterization and antibacterial activity of determination of

As multidrug-resistant microorganisms are becoming increasingly problematic, it is becoming evident that a single antibacterial agent is insufficient for combatting these pathogens, and a more multifaceted approach is required. Herein, mix-extract of rosemary and thyme is used to biosynthesize silver nanoparticles (AgNPs), and surface layer protein (SLp) is obtained by Lactiplantibacillus plantarum strain as a capping agent. Thus, a hybrid antibacterial agent (SLp-AgNPs) is prepared and investigated for possible synergistic antibacterial mechanisms. The characterization of the SLp-AgNPs agent was conducted using a range of analytical techniques, including X-ray diffraction (XRD), energy dispersive spectrum (EDX), scanning electron microscopy (SEM), and Raman spectroscopy. Characterization results have revealed the AgNPs have been successfully synthesized and functionalized by the SLPs, changing AgO, Ag2O and Ag2O3. According to the disk diffusion test, the increase in the SLp ratio resulted in lower inhibitory concentrations against Staphylococcus aureus than the bare AgNPs at the end of 24 hours. The examination of the growth kinetics of the microorganisms revealed that E. coli lost viability entirely after 24 hours, while S. aureus lost viability after 48 hours. A substantial antimicrobial effect was observed in the 5% AgNP-SLp (1:1) colloidal biohybrid solution.As for E. coli, a faster decline trend was shown in the bacterial population as to be a decrease from 8.17 log CFU mL-1 to <1 log CFU mL-1 after 8 hours. Bacterial cells exposed to AgNP-SLp colloidal biohybrid solution exhibited higher cell membrane permeability, resulting in more severe cell death compared with bare AgNPs. The antibacterial activity success of this hybrid agent is probably due to the enhanced adhesion of SLp to bacteria and the effect of its unique lattice structure on the release of silver ion. Therefore, this study demonstrated that AgNP-SLp colloidal biohybrid solution has the potential as an effective antibacterial hybrid agent against bacterial cells.