Highly Efficient Antimicrobial Activity of CuxFeyOz Nanoparticles against Important Human Pathogens

Abstract

The development of innovative antimicrobial materials is crucial in thwarting infectious diseases caused by microbes, as drug-resistant pathogens are increasing in both number and capacity to detoxify the antimicrobial drugs used today. An ideal antimicrobial material should inhibit a wide variety of bacteria in a short period of time, be less or not toxic to normal cells, and the fabrication or synthesis process should be cheap and easy. We report a one-step microwave-assisted hydrothermal synthesis of mixed composite CuxFeyOz (Fe2O3/Cu2O/CuO/CuFe2O) nanoparticles (NPs) as an excellent antimicrobial material. The 1 mg/mL CuxFeyOz NPs with the composition 36% CuFeO2, 28% Cu2O and 36% Fe2O3 have a general antimicrobial activity greater than 5 log reduction within 4 h against nine important human pathogenic bacteria (including drug-resistant bacteria as well as Gram-positive and Gram-negative strains). For example, they induced a >9 log reduction in Escherichia coli B viability after 15 min of incubation, and an ~8 log reduction in multidrug-resistant Klebsiella pneumoniae after 4 h incubation. Cytotoxicity tests against mouse fibroblast cells showed about 74% viability when exposed to 1 mg/mL CuxFeyOz NPs for 24 h, compared to the 20% viability for 1 mg/mL pure Cu2O NPs synthesized by the same method. These results show that the CuxFeyOz composite NPs are a highly efficient, low-toxicity and cheap antimicrobial material that has promising potential for applications in medical and food safety.

Rapid Catalytic Water Disinfection from Earth Abundant Ca2Fe2O5 Brownmillerite

“…[40,41] Indeed, previous studies using iron oxide based antimicrobial agents have equivalently poor performance. [42,43] The only material found in literature, that does not contain silver to have equivalent or improved performance compared to our Ca 2 Fe 2 O 5 material is Cu x Fe y O z reported by Zhu et al [44] This copper containing material exhibited a large amount of copper ion leakage leading to bacterial death, which therefore cannot be used for large scale water disinfection.…”

“…XRD studies were performed by using powder XRD measurements performed on a Bruker D8 Advance diffractometer using copper radiation (Cu Kα = 1.54180 Å) with Bragg-Brentano geometry and S7 of the Supporting Information for full details). [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] www.advsustainsys.com LynxEye (1D) detector. The tube voltage and current were set to 40 kV and 40 mA, respectively.…”

“…Finally, to effectively assess the feasibility of the Ca 2 Fe 2 O 5 nanopowder we have compared our log reduction in bacterial concentration (and the time taken to achieve the reduction) with literature (Figure 8). [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] Most literature reports rely on the silver based antimicrobial agents, which are impractical for large scale water or sewage treatment.…”

“…Figure 8. Comparison of disinfection performance of various materials with data in literature (see TableS7of the Supporting Information for full details) [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. …”

The Promise of Metal-Doped Iron Oxide Nanoparticles as Antimicrobial Agent

“…Similarly, the insertion of foreign metal particles into IONPs alter their physicochemical, as well as biological, electrical, and optical, properties and improve performance compared to bare IONPs . IONPs are doped with several metals, and their oxides, such as Ni, , Cu, , Co, Zn, , Se, Mo, Au, , ZnO, , CuO, exhibit antimicrobial activity toward pathogenic bacteria.…”