Silver-Protein Nanocomposites as Antimicrobial Agents

Abstract

The use of nanomaterials alone or in composites with proteins is a promising alternative to inhibit pathogenic bacteria. In this regard, this study used seed proteins from both fenugreek (Trigonella foenum-graecum L.) (FNP) and mung bean (Viga radiate) (MNP), with silver nanoparticles (Ag-NPs) and nanocomposites of either Ag-NPs plus FNP (Ag-FNP) or Ag-NPs plus MNP (Ag-MNP) as inhibitory agents against pathogenic bacteria. FNP and MNP were isolated from fenugreek seeds and mung bean seeds, respectively, and fractionated using Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis (SDS–PAGE). Both FNP and MNP were immobilized with Ag-NPs to synthesize the nanocomposites Ag-FNP and Ag-MNP, respectively. The physicochemical characteristics of Ag-NPs and their composites with proteins were studied by X-ray Diffraction (XRD), dynamic light scattering (DLS), the zeta potential, Scanning and Transmission Electron Microscopy (SEM and TEM, respectively), Atomic Force Microscopy (AFM), and the Brunauer–Emmett–Teller isotherm (BET), elucidating their structural parameters, size distribution, size charges, size surface morphology, particle shape, dimensional forms of particles, and specific surface area, respectively. The sole proteins, Ag-NPs, and their nanocomposites inhibited pathogenic Gram-positive and Gram-negative bacteria. The inhibitory activities of both nanocomposites (Ag-FNP and Ag-MNP) were more than those obtained by either Ag-NPs or proteins (FNP, MNP). Minimum inhibitory concentrations (MICs) of Ag-FNP were very low (20 and 10 µg mL−1) against Salmonellatyphimurium and Pseudomonasaerugenosa, respectively, but higher (162 µg mL−1) against E. coli and Listeriamonocytogenes. MICs of Ag-MNP were also very low (20 µg mL−1) against Staphylococcusaureus but higher (325 µg mL−1) against Listeriamonocytogenes. TEM images of Staphylococcusaureus and Salmonellatyphimurium, treated with Ag-FNP and Ag-MNP, at their MIC values, showed asymmetric, wrinkled exterior surfaces, cell deformations, cell depressions, and diminished cell numbers.

Inhibitory action of three lactic acid bacteria cultures on some food-borne pathogens during pickling of green olive fruits

“…Several studies reported the isolation of different bacterial pathogens from pickles ( Chaiyasut et al., 2018 ) . Some of these bacterial isolates showed resistance to antibiotics ( Sitohy et al., 2021 ) . This showed an interested challenge to develop pickling processes with complete hygienic procedures.…”

“…They were grown into BHI broth incubated at 37 °C for almost 18h till obtaining actively exponentially growing cells. CFS of L. plantarum LPS10 was added (2% V/V) to these actively growing bacterial cells except control and further incubated at 37 °C for 6 h, then the treated bacterial cells were subjected to TEM analysis as given previously ( Sitohy et al., 2013 , 2021 ; Abdel-Shafi et al., 2016 ) .…”

The Healing Capability of Clove Flower Extract (CFE) in Streptozotocin-Induced (STZ-Induced) Diabetic Rat Wounds Infected with Multidrug Resistant Bacteria

“…A total of about 64 bacterial isolates were obtained. All of these isolates were assayed for antibiotic sensitivity using 13 antibiotics that assimilate 7 antibiotic types such as cephalosporines, polymexins, penicillins, fluroquinolones, aminoglycosides, macrolides, and sulphonamides [ 19 , 20 , 69 ]. Results were taken according to CLSI [ 70 ].…”

“…MDR- P. mirabilis is one of the most prevalent microbes to exist in diabetic foot ulcers (DFU) [ 12 ]. There is a vast need to search for other innovative therapies based on using natural plant extract either singly or in combination with antibiotics [ 11 ], probiotics [ 3 , 13 , 14 , 15 , 16 , 17 ], natural and modified proteins [ 18 , 19 ], nanoparticles [ 20 ], and phage therapy [ 21 ].…”

Nanomaterials and Microorganisms: From Green Synthesis to Antibacterial Applications in Medicine and Agriculture

“…Thus, it was demonstrated that green synthesis is a promising method for the production of novel nanopesticides. Sitohy et al developed a different green synthesis approach by combining Ag NPs, which are well known for their antibacterial efficiency, with plant seed proteins to produce nanocomposites with higher antibacterial efficiency than each of the single components [ 2 ]. The proteins acted as stabilizers of Ag and also increased the antibacterial potency of the nanocomposite, plausibly due to positively charged and hydrophobic amino acid residues which facilitated contact with the bacterial cell.…”