Antimicrobial Applications of Green Synthesized Bimetallic Nanoparticles from Ocimum basilicum

Abstract

Antibiotic resistance is an important and emerging alarm for public health that requires development of new potential antibacterial strategies. In recent years, nanoscale materials have emerged as an alternative way to fight pathogens. Many researchers have shown great interest in nanoparticles (NPs) using noble metals, such as silver, gold, and platinum, even though numerous nanomaterials have shown toxicity. To overcome the problem of toxicity, nanotechnology merged with green chemistry to synthesize nature-friendly nanoparticles from plants. Here, we describe the synthesis of NPs using silver (AgNPs) and platinum (PtNPs) alone or in combination (AgPtNPs) in the presence of Ocimum basilicum (O. basilicum) leaf extract. O. basilicum is a well-known medicinal plant with antibacterial compounds. A preliminary chemical–physical characterization of the extract was conducted. The size, shape and elemental analysis were carried out using UV–Visible spectroscopy, dynamic light scattering (DLS), and zeta potential. Transmission electron microscopy (TEM) confirmed polydisperse NPs with spherical shape. The size of the particles was approximately 59 nm, confirmed by DLS analysis, and the polydisperse index was 0.159. Fourier transform infrared (FTIR) demonstrated an effective and selective capping of the phytoconstituents on the NPs. The cytotoxic activities of AgNPs, PtNPs and AgPtNPs were assessed on different epithelial cell models, using the 3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide (MTT) cell proliferation assay, and discovered low toxicity, with a cell viability of 80%. The antibacterial potential of the NPs was evaluated against Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Klebsiella pneumonia (K. pneumoniae), and Staphylococcus aureus (S. aureus) strains. Minimum inhibitory concentration (MIC) assays showed AgPtNP activity till the least concentration of NPs (3.15–1.56 µg/mL) against ATCC, MS, and MDR E. coli, E. faecalis, and S. aureus and the Kirby–Bauer method showed that AgPtNPs gave a zone of inhibition for Gram-positive and Gram-negative bacteria in a range of 9–25 mm. In addition, we obtained AgPtNP synergistic activity in combination with vancomycin or ampicillin antibiotics. Taken together, these results indicate that bimetallic nanoparticles, synthesized from O. basilicum leaf extract, could represent a natural, ecofriendly, cheap, and safe method to produce alternative antibacterial strategies with low cytotoxicity.

Biogenic Synthesis of Multifunctional Silver Oxide Nanoparticles (Ag2ONPs) Using Parieteria alsinaefolia Delile Aqueous Extract and Assessment of Their Diverse Biological Applications

“…Figure 2 indicates the biosynthesis peaked after three hours. The findings of our research utilizing UV-Vis spectroscopy are in accordance with those of an earlier study that used a variety of plant extracts [46][47][48].…”

Some biological potential of silver nanoparticles synthesized from Ocimum basilicum L.

“…Silver and platinum nanoparticles were synthesized from O. basilicum L. leaf extracts by green synthesis method and their antibacterial activity was investigated by using them separately and in combination. The MIC value for the AgNPs was determined as 3.12 µg mL -1 and 6.25 µg mL -1 for gram positive and negative bacteria, respectively [24]. The antibacterial effect of AgNPs which is formed by combining O. basilicum and Hibiscus sabdariffa L. plant extracts were investigated, and the MIC value was determined as 6.25 µg mL -1 [26].…”

“…Figure 3 The SEM images of synthesized AgNP Malapermal et al, (2017) [23], More et al (2022)[24] were reported that synthesized AgNPs by Ocimum species were found to be crystalline and relatively spherical Melkamu et al (2022) [25]. reported that as a result of SEM analysis of Ocimum sanctum-AgNP had a various sizes including spherical, cubic and flake-shaped (20 nm).…”

Phytosynthesis of Silver Nanoparticles Using Oscimum sanctum Leaf Extract and Studies on Its Antidiabetic, Antioxidant, and Antibacterial Properties

“…41−43 However, literature indicates that on increasing leaf extract concentration and AgNO 3 mM concentration beyond a certain level, the rate of Ag NP formation decreases. 44,45 It is also found that on increasing the reaction time and temperature, Ag NP synthesis rate increases. 44,45 2.4.…”