Penicillium chrysogenum-Derived Silver Nanoparticles: Explorationof Their Antibacterial and Biofilm Inhibitory Activity Againstthe Standard and Pathogenic Acinetobacter baumannii Compared to Tetracycline

Abstract: This study was aimed to evaluate the antibacterial and biofilm inhibitory activity of Penicillium chrysogenum-derivedsilver nanoparticles (AgNPs) against the standard and pathogenic Acinetobacter baumannii using a 96-well microtiterplate-based method. The AgNPs were characterized by using UV–Vis, TEM, AFM, XRD, DLS, Zeta potential, and FT-IR.The nanoparticles (NPs) were fabricated with a spherical shape and an average hydrodynamic diameter of 48.2 nm. Theminimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs were found to be 4and 32 lg/mL respectively, whereas the MIC and MBC of tetracycline were found to be 1024 and 8192 lg/mL against A.baumannii (ATCC 19606). The AgNPs and tetracycline represented considerable biofilm inhibitory activity against boththe standard and pathogenic A. baumannii at the studied concentrations. However, the AgNPs depicted higher potency toinhibit the process of biofilm formation of some pathogenic A. baumannii species compared to tetracycline. The AgNPs atthe concentration of 0.5*MIC (2 lg/mL) inhibited above 90% biofilm inhibition, whereas tetracycline reached 90% biofilminhibition at the concentration of 4*MIC (4096 lg/mL) against A. baumannii (ATCC 19606). However, further studies arerequired to evaluate the biofilm inhibitory efficacy of biogenic AgNPs in vivo. Keywords: Silver nanoparticles, Biosynthesis, Antibacterial activity, Biofilm inhibitory activit

Bioengineering of green-synthesized silver nanoparticles: in vitro physicochemical, antibacterial, biofilm inhibitory, anticoagulant, and antioxidant performance

Green-synthesized nanobiomaterials can be engineered as smart nanomedicine platforms for diagnostic and therapeutic purposes in medicine. Herein, we investigated the bioengineering of silver nanoparticles (AgNPs) and evaluated their physicochemical, antibacterial, biofilm inhibitory, anticoagulant, and antioxidant performance. Characterization of the AgNPs was performed utilizing UV–visible, transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FT-IR). The spherical shaped AgNPs were proven by TEM and SEM techniques. Moreover, the XRD diffraction patterns demonstrated that the nanoparticles were in a crystalline state. The DLS represented the hydrodynamic particle size of the NPs at 49.62 nm at a pH of 9. The calculated minimum inhibitory concentration (MIC) of AgNPs toward Staphylococcus aureus (ATCC 25923) was 8 μg mL−1, which was almost similar to tetracycline by the value of 4 μg mL−1. Moreover, the minimum bactericidal concentration (MBC) of AgNPs was 64 μg mL−1, which was significantly less than the determined value of 256 μg mL−1 for tetracycline. Considering the pathogenic and standard S. aureus, the evaluated concentrations of AgNPs and tetracycline showed significant biofilm inhibitory performance. Furthermore, the bioengineered AgNPs exhibited significant anticoagulant activity at 500 μg mL−1 compared to saline (P < 0.001). In addition, the biogenic AgNPs inhibited 69.73 ± 0.56% of DPPH free radicals at 500 μg mL−1, indicating considerable antioxidant potential