Abstract
Silver nanoparticles (AgNPs) have been used as antibacterial, antifungal, antiviral, anti-inflammtory, and antiangiogenic due to its unique properties such as physical, chemical, and biological properties. The present study was aimed to investigate antibacterial and anti-biofilm activities of silver nanoparticles alone and in combination with conventional antibiotics against various human pathogenic bacteria. Here, we show that a simple, reliable, cost effective and green method for the synthesis of AgNPs by treating silver ions with leaf extract of Allophylus cobbe. The A. cobbe-mediated synthesis of AgNPs (AgNPs) was characterized by ultraviolet-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the antibacterial and anti-biofilm activity of antibiotics or AgNPs, or combinations of AgNPs with an antibiotic was evaluated using a series of assays: such as in vitro killing assay, disc diffusion assay, biofilm inhibition, and reactive oxygen species generation in Pseudomonas aeruginosa, Shigella flexneri, Staphylococcus aureus, and Streptococcus pneumonia. The results suggest that, in combination with antibiotics, there were significant antimicrobial and anti-biofilm effects at lowest concentration of AgNPs using a novel plant extract of A. cobbe, otherwise sublethal concentrations of the antibiotics. The significant enhancing effects were observed for ampicillin and vancomycin against Gram-negative and Gram-positive bacteria, respectively. These data suggest that combining antibiotics and biogenic AgNPs can be used therapeutically for the treatment of infectious diseases caused by bacteria. This study presented evidence of antibacterial and anti-biofilm effects of A. cobbe-mediated synthesis of AgNPs and their enhanced capacity against various human pathogenic bacteria. These results suggest that AgNPs could be used as an adjuvant for the treatment of infectious diseases.
Highlights
Nanotechnology is a promising field for generating new types of nanomaterials with biomedical applications [1]
There has been significant interest in antibacterial nanoparticles as a means to overcome the problem of drug resistance in various pathogenic microorganisms
The antibacterial activity of the selected antibiotics was increased in the presence of AgNPs against test strains
Summary
Nanotechnology is a promising field for generating new types of nanomaterials with biomedical applications [1]. Silver nanoparticles (AgNPs) have attracted significant interest among the emerging nanoproducts because of their unique properties and increasing use for various applications in nanomedicine. Because the control of particle size and shape is an important factor for various biomedical applications, the use of biological methods to synthesize AgNPs is an environmentally friendly alternative. These methods involve synthesizing AgNPs using bacterial proteins that can exert control over the shape, size, and monodispersity of the nanoparticles by varying parameters such as the type of microorganism, growth stage, growth medium, synthesis conditions, pH, substrate concentrations, temperature, and reaction time [4]
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