Copper/Silver Bimetallic Nanoparticles Supported on Aluminosilicate Geomaterials as Antibacterial Agents

Abstract

This study aims to understand how properties of modified aluminosilicate geomaterials influence the antibacterial performance of nanocomposites when prepared with bimetallic nanoparticles (NPs).Copper/silver (Cu/Ag) bimetallic NPs were synthesized in the presence of imogolite (Imo), montmorillonite (Mtt), or zeolite (Zeo) using a simple onepot method and characterized for their crystal phases, micro-and nanomorphologies, particle size, elemental composition, and electrophoretic mobility. The antibacterial activity was evaluated through minimum inhibition concentration assays of NPs and nanocomposites for Gram (−) Escherichia coli and Gram (+) Staphylococcus aureus bacteria. Deposition of metallic Cu 0 , Ag 0 , and cuprite NPs was confirmed in Zeo_Cu/Ag and Imo_Cu/Ag nanocomposites, whereas only Cu 0 and Ag 0 were identified in Mtt_Cu/Ag. The bimetallic NPs were more uniformly distributed on Zeo and Mtt than Imo. Particle sizes of 28.1 ± 5.0, 9.4 ± 2.3, 10.1 ± 1.7, and 12 ± 1.3 nm were determined for Cu/Ag NPs, Imo_Cu/Ag, Mtt_Cu/Ag, and Zeo_Cu/Ag, respectively. The release rate of Cu and Ag ions from Zeo_Cu/Ag was higher than those of pristine Cu/Ag NPs and the other two nanocomposites. The antimicrobial action of bimetallic NPs and nanocomposites was dose-dependent in relation to the concentration of concerned materials and their stability in the medium. The physicochemical characteristics of Zeo resulted in a homogeneous distribution and low oxidation and agglomeration of Cu/Ag NPs, consequently increasing the antibacterial activity. Results of this study highlight the benefits of using a geomaterial support to achieve high antibacterial activity of bimetallic NPs, which could help reduce the consumption of pure Cu/Ag salts in NP-based antibacterial applications.

Synergistic antibacterial mechanism of silver-copper bimetallic nanoparticles

“…Relevant studies suggest that the incorporation of silver components significantly reduces the oxidation tendencies of CuNPs. The formation of Ag-Cu NPs reduces oxygen ingress, resulting in a more stable structure compared to monometallic conditions, allowing for slow ion release, both favorable for synergistic interactions between the two metals ( Cruces et al, 2022 ). Ahmadinejad et al investigated the aging of synthesized Ag-Cu alloy nanoparticles and found them to be more stable than pure Cu nanoparticles, attributing this stability to the protective effect of a thin Ag shell ( Ahmadinejad and Mahdieh, 2022 ).…”

Synthesis of Bimetallic Nanoparticles and Applications—An Updated Review

“…Both mono and bimetallic nanoparticles are suitable for applications in various fields, including biomedical, biosensors, nanomedicine, imaging, wastewater treatment, oil and gas industries, agriculture/food processing and gene/drug delivery [14][15][16][17][18][19][20]. In addition, antimicrobial and anticancer activities of bimetallic nanoparticles have also been investigated extensively [21][22][23][24][25][26].…”

Enhancing the Antibacterial Properties of Magnesium Alloys with Copper-Doped Anhydrous Calcium Phosphate Nanoparticles Embedded into the Polycaprolactone Coating for Medical Implants

“…Copper (Cu), one of the important trace elements in vivo, exhibits excellent antibacterial properties. , Meanwhile, it is important in many enzymatic reactions in vivo and can enhance cell viability and osteoblast proliferation, too . Currently, mainly elemental copper or copper oxide nanoparticles are studied; nevertheless, there are few studies on the incorporation of copper into nanoparticles in the form of ions. , Copper ions can replace part of calcium ions in calcium salts, and their slow release from the compound has been confirmed to be antibacterial .…”