Design and Synthesis of Copper Nanobiomaterials with Antimicrobial Properties.

In this work, nanostructured copper materials have been designed, synthetized, and evaluated in order to produce a more efficient and sustainable copper bionanohybrid with catalytical and antimicrobial properties. Thus, conditions are sought where the most critical steps are reduced or minimized, such as the use of reducing agents or the cryogenization step. In addition, the new materials have been characterized through different techniques, and their oxidative and reductive capacities, as well as their antimicrobial activity, have been evaluated. The addition of different quantities of a reducing agent in the synthesis method generated copper bionanohybrids with different metallic species, nanoparticles sizes, and structures. The antimicrobial properties of the bionanohybrids were studied against different strains of Gram-positive and Gram-negative bacteria through two different methods: by counting the CFU and via the disk diffusion test, respectively. The bionanohybrids have demonstrated that different efficiencies depending on the bacterial strain were confronted with. The Cu-PHOS-100% R hybrids with the highest percentage of reduction showed the best antimicrobial efficiency against Escherichia coli and Klebsiella pneumoniae bacteria (>96 or >77% in 4 h, respectively) compared to 31% bacteria reduction using Cu-PHOS-0% R . Also, the antimicrobial activity against Bacillus subtilis materials was obtained with Cu-PHOS-100% R (31 mm inhibition zone and 125 μg/mL minimum inhibitory concentration value). Interestingly, the better antimicrobial activity of the nanobiohybrids against Gram-positive bacteria Mycobacterium smegmatis was obtained with some with a lower reduction step in the synthesis, Cu-PHOS-10% R or Cu-PHOS-20% R (>94% bacterial reduction in 4 h).