Synthesis and design of Ag–Fe bimetallic nanoparticles as antimicrobial synergistic combination therapies against clinically relevant pathogens

Abstract

The inappropriate use of antibiotics and the inadequate control of infections have led to the emergence of drug-resistant strains. In recent years, metallo-pharmaceutics and metallic nanoparticles have been proposed as potential alternative antimicrobials due to their broad-spectrum antimicrobial properties. Moreover, recent findings have shown that combinations of transition metal compounds can exhibit synergistic antimicrobial properties. Therefore, the synthesis and design of bimetallic nanoparticles is a field worth exploring to harness the interactions between groups of metals and organic complex structures found in different microbial targets, towards the development of more efficient combinatorial antimicrobials composed of synergistic metals. In this study, we present a green synthesis of Ag–Fe bimetallic nanoparticles using an aqueous extract from the leaves of Gardenia jasminoides. The characterization of the nanoparticles demonstrated that the synthesis methodology produces homogenously distributed core–shell Ag–Fe structures with spherical shapes and average diameter sizes of 13 nm (± 6.3 nm). The Ag–Fe bimetallic nanoparticles showed magnetic and antimicrobial properties; the latter were evaluated against six different, clinically relevant multi-drug-resistant microbial strains. The Ag–Fe bimetallic nanoparticles exhibited an antimicrobial (bactericidal) synergistic effect between the two metals composing the bimetallic nanoparticles compared to the effects of the mono-metallic nanoparticles against yeast and both Gram-positive and Gram-negative multidrug-resistant bacteria. Our results provide insight towards the design of bimetallic nanoparticles, synthesized through green chemistry methodologies, to develop synergistic combinatorial antimicrobials with possible applications in both industrial processes and the treatment of infections caused by clinically relevant drug-resistant strains.

Nanomaterial-Based Antifungal Therapies to Combat Fungal Diseases Aspergillosis, Coccidioidomycosis, Mucormycosis, and Candidiasis

“…As an alternative to classic drugs used to fight fungal infections, the search for new treatments has become necessary. Like those made from Ag, Au, ZnO, and TiO 2 , metal nanoparticles have great potential to be used as antimicrobial agents against various microorganisms, from bacteria to fungi [17,[86][87][88][89][90][91]. These metallic nanoparticles are continuously studied to overcome microbial infections/growth.…”

Recent Advances in Surface-Enhanced Raman Scattering Magnetic Plasmonic Particles for Bioapplications

“…On the other hand, the Au shell supplements better heating in magnetic hyperthermia [ 21 ] and Fe-Au core-shell MPPs exhibited a higher transverse relaxivity comparing with Fe 3 O 4 NPs in bioimaging [ 51 ]. Another combination between magnetic and plasmonic is Ag and Fe based on MPPs that are similar with Au-Fe MPPs in sensitive specific detection [ 36 , 38 , 43 , 59 ], better bioimage [ 28 ] and moreover, they show antibacterial synergistic ability [ 60 , 61 ]. Padilla-Cruz et al reported that core-shell Ag-Fe spherical particles showed magnetic and antimicrobial properties [ 60 ].…”

“…Another combination between magnetic and plasmonic is Ag and Fe based on MPPs that are similar with Au-Fe MPPs in sensitive specific detection [ 36 , 38 , 43 , 59 ], better bioimage [ 28 ] and moreover, they show antibacterial synergistic ability [ 60 , 61 ]. Padilla-Cruz et al reported that core-shell Ag-Fe spherical particles showed magnetic and antimicrobial properties [ 60 ]. These Ag-Fe NPs possessed the antibacterial synergistic effect, compared to Ag NPs or Fe NPs, against both Gram-positive and Gram-negative multidrug-resistant bacteria and yeast.…”

“…The Fe NPs have not showed the antibacterial property. Values of minimal inhibitory concentration of Ag NPs and Ag-Fe NPs are the same at 125 ppm in S.aureus ATCC 6538 case, 62.5 and 31.25 ppm in P. aeruginosa ATCC 27,853 case, 31.25 and 15.62 ppm in multidrug-resistant P. aeruginosa case, the same at 125 ppm in E. Coli ATCC 11,229 case, and 125 and 62.5 ppm in C. albicans case [ 60 ].…”

Molecular dynamics study on structural and atomic evolution between Au and Ni nanoparticles through coalescence

“…It is well known that the physical and chemical properties of metallic nanomaterials depend strongly on their size and morphology 1 – 3 . Heterogeneous bimetallic nanoparticles (NPs) consisting of magnetic and noble metals possess enhanced magnetic, optical, and catalytic performance compared to the corresponding monometallic NPs 4 , 5 .…”