Biogenic Gold Nanoparticles as Potent Antibacterial and Antibiofilm Nano-Antibiotics against Pseudomonas aeruginosa

Abstract

Plant-based synthesis of eco-friendly nanoparticles has widespread applications in many fields, including medicine. Biofilm—a shield for pathogenic microorganisms—once formed, is difficult to destroy with antibiotics, making the pathogen resistant. Here, we synthesized gold nanoparticles (AuNPs) using the stem of an Ayurvedic medicinal plant, Tinospora cordifolia, and studied the action of AuNPs against Pseudomonas aeruginosa PAO1 biofilm. The synthesized AuNPs were characterized by techniques such as ultraviolet-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray diffraction, X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy. The AuNPs were spherically shaped with an average size of 16.1 nm. Further, the subminimum inhibitory concentrations (MICs) of AuNPs (50, 100, and 150 µg/mL) greatly affected the biofilm-forming ability of P. aeruginosa, as observed by crystal violet assay and SEM, which showed a decrease in the number of biofilm-forming cells with increasing AuNP concentration. This was further justified by confocal laser scanning microscopy (CLSM), which showed irregularities in the structure of the biofilm at the sub-MIC of AuNPs. Further, the interaction of AuNPs with PAO1 at the highest sub-MIC (150 µg/mL) showed the internalization of the nanoparticles, probably affecting the tendency of PAO1 to colonize on the surface of the nanoparticles. This study suggests that green-synthesized AuNPs can be used as effective nano-antibiotics against biofilm-related infections caused by P. aeruginosa.

Biofabricated Fatty Acids-Capped Silver Nanoparticles as Potential Antibacterial, Antifungal, Antibiofilm and Anticancer Agents

“…Under identical conditions, Gram-positive MRSA cells were observed with significant structural damage along with tremendous bulging and deep cuts in cell membrane ( Figure 8 e,f), which indicated increased cytoplasmic granularity likely due to prompted interaction and internalization of LIV-AgNPs as compared to untreated cells ( Figure 8 d) [ 5 ]. Similarly, in the case of fungi, the LIV-AgNPs exposed C. albicans cells showed significant changes in native morphology such as deep pits in cells compared to untreated control ( Figure 8 h,i) as reported elsewhere [ 32 ]. Besides, Anuj et al [ 33 ] have demonstrated a steady release of Ag + from AgNPs and thus accumulated cations can destabilize cell membrane to combat with efflux-mediated drug resistance in Gram-negative bacteria.…”

Au Nanoclusters Ameliorate Shigella Infectious Colitis by Inducing Oxidative Stress

“…The results proved the unexpected antibacterial power of Au NCs against Shigella . Au NCs are also expected to pass through the biofilms of Pseudomonas aeruginosa and Escherichia coli to kill pathogens, 51 , 52 potentially because tiny particles destroy the stability of the biofilm through some mechanisms. 53 We further explored the mechanism by focusing on ROS, which are essential for antibacterial activity.…”

Proanthocyanin‐Capped Biogenic TiO2 Nanoparticles with Enhanced Penetration, Antibacterial and ROS Mediated Inhibition of Bacteria Proliferation and Biofilm Formation: A Comparative Approach

“…The ICP‐MS instrument was calibrated by standard solutions of Ti ions. In parallel, intracellular uptake of bare and GSE‐TiO 2 NPs in bacterial cells was evaluated qualitatively with TEM [54] . In detail, the P. aeruginosa and S. saprophyticus cells were incubated with 6.25 μg mL −1 of both TiO 2 NPs types for 24 h at 37 °C.…”