Phytochemical-Mediated Green Synthesis of Silver, Copper, and Ag-Cu Bimetallic Nanoparticles Using Peganum harmala...

This study explores the green synthesis of silver (Ag-NPs), copper (Cu-NPs), and silver-copper bimetallic nanoparticles (Ag-Cu Bimetallic NPs) using the leaf extract of Peganum harmala, a sustainable and renewable plant source. This eco-friendly synthesis method avoids hazardous chemicals and minimizes waste, advancing the principles of green nanotechnology. Characterization demonstrated distinct properties; Ag-NPs, Cu-NPs, and Ag-Cu bimetallic NPs exhibited surface plasmon resonance peaks at 425 nm, 555 nm, and 525 nm, respectively, and crystallite sizes of 21.42 nm, 21.40 nm, and 26.29 nm as confirmed by X-ray diffraction. Morphological analysis revealed spherical Ag-NPs, flake-like Cu-NPs, and a mix of cubic and spherical Ag-Cu NPs. Catalytic activity tests showed Ag-Cu bimetallic NPs achieved 95% degradation of methylene blue dye, highlighting their potential in environmental remediation. Antibacterial assays demonstrated that Ag-NPs exhibited the highest inhibition zones against Bacillus subtilis (27.0 mm) and Escherichia coli (27.67 mm), while Cu-NPs were effective against Klebsiella pneumoniae at higher concentrations. Ag-NPs also exhibited significant antifungal activity, particularly against Aspergillus niger (15.00 mm). Antioxidant assays revealed Ag-Cu bimetallic NPs displayed the highest free radical scavenging capacity (59.18%), followed by Ag-NPs (35.41%). Cytotoxicity tests indicated Ag-Cu bimetallic NPs had an IC₅₀ value of 6.13 µg/mL, reflecting high cytotoxicity, whereas Ag-NPs demonstrated better biocompatibility. Hemolysis assays showed P. harmala extract had the highest hemolytic activity (IC₅₀ = 4.49 µg/mL). This study provides a scalable, sustainable method for synthesizing multifunctional nanoparticles with promising applications in environmental remediation, antimicrobial resistance management, and biomedicine. Future studies should focus on scaling up this sustainable synthesis method, investigating the biological interactions of these nanoparticles, and optimizing their dosages to reduce potential environmental and health risks.