CuAgNPs-enzyme Biohybrids as Antimicrobial nanomaterials

Multidrug-resistant bacterial infections have become major threats to public health worldwide. Thus, bimetallic Ag-Cu nanoparticles-enzyme biohybrids has been developed. Different bimetallic bionanohybrids were synthesized with different contents of Ag, by the direct incubation of a previous synthesized Cu3(PO4)2NPs-CALB hybrid with silver salt in aqueous media and r.t. They were fully characterized, determining silver phosphate as metal species, and different nanoparticles sizes depending on the amount of silver used. HAADF-STEM analyses demonstrated the formation of individual Ag3PO4 NPs on the Cu-CALB nanoflowers. The catalytic reductase or oxidase-like activities of the bimetallic biohybrids was also affected being higher values when lower amount of silver was used. This effect was corroborated in their antimicrobial efficacy against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Mycobacterium smegmatis. Results indicate that the presence of small content on silver in the bimetallic hybrids highly enhanced the antibacterial activity compared to initial Cu36@CALB hybrid. Optimal amount of silver has been found corresponding to the bimetallic Ag4Cu32@CALB hybrid which showed the strongest antibacterial effect, with log reductions of 7.6, 4.3 and 3.9 for K. pneumoniae, P. aeruginosa, E. coli, and 1.8 for M. smegmatis. Overall, these novel nanomaterials are a promising alternative for fight against different pathogens.