Intrafibrillar dispersion of cuprous oxide (Cu2O) nanoflowers within cotton cellulose fabrics for permanent antibacterial, antifungal and antiviral activity

Authors: Hillyer, Matthew; Nam, Sunghyun; Condon, Brian

Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2022
Publication Date: 11/9/2022
Citation: Hillyer, M.B., Nam, S., Condon, B.D. 2022. Intrafibrillar dispersion of cuprous oxide (Cu2O) nanoflowers within cotton cellulose fabrics for permanent antibacterial, antifungal and antiviral activity. Molecules. 27:7706. https://doi.org/10.3390/molecules27227706.
DOI: https://doi.org/10.3390/molecules27227706

Interpretive Summary: Cotton fabrics with multifunctional properties infused with metal oxide nanoflowers for antibacterial applications are becoming increasingly popular. Copper oxide nanomaterials have gained popularity for their synthetic versatility, microbicidal properties and cost-effectiveness compared to other metals. This study has presented a method in which cuprous oxide nanoflowers (Cu2O NFs) are synthesized in situ from a copper (II) precursor under mild conditions and without added chemical reducing agents. The internal formation of Cu2O NFs (72.0 ± 51.8 nm) within the cotton fiber structure was confirmed by TEM. These Cu2O NF cotton fabrics demonstrated remarkable laundering durability, releasing only 19% of copper content after 50 home laundering cycles determined by ICP-MS and UV-vis using a calculated calibration curve (R2 = 0.9979). The washing durability of the internally-produced Cu2O NFs was verified by the persistence of superior broad-spectrum antibacterial, antifungal and antiviral activity with greater than 99.99% inhibition against K. pneumoniae, E. coli, S. aureus and A. niger and =90% inhibition against Human coronavirus, strain 229E, even after 50 home laundering cycles.

Technical Abstract: With increasingly frequent highly infectious global pandemics, the textile industry has responded by developing new commercial fabric products by incorporating antibacterial metal oxide nanoparticles, particularly copper oxide in cleaning products and personal care items including antimicrobial wipes, hospital gowns and masks. Current methods use a surface adsorption method to functionalize nanomaterials to fibers. However, this results in poor durability and decreased antimicrobial activity after consecutive launderings. In this study, cuprous oxide nanoparticles with nanoflower morphology (Cu2O nanoflowers) are synthesized in situ within the cotton fiber under mild conditions and without added chemical reducing agents from a copper (II) precursor with an average maximal Feret diameter of 72.0 ± 51.8 nm and concentration of 17,489 ± 15 mg/kg. Analysis of the Cu2O NF-infused cotton fiber cross-section by transmission electron microscopy (TEM) confirmed the internal formation, and X-ray photoelectron spectroscopy (XPS) confirmed the copper (I) reduced oxidation state. An exponential correlation (R2 = 0.9979) between the UV-vis surface plasmon resonance (SPR) intensity at 320 nm of the Cu2O NFs and the concentration of copper in cotton was determined. The laundering durability of the Cu2O NF-cotton fabric was investigated, and the superior nanoparticle-leach resistance was observed, with the fabrics releasing only 19% of copper after 50 home laundering cycles. The internally immobilized Cu2O NFs within the cotton fiber exhibited continuing antibacterial activity (=99.995%) against K. pneumoniae, E. coli and S. aureus), complete antifungal activity (100%) against A. niger and antiviral activity (=90%) against Human coronavirus, strain 229E, even after 50 laundering cycles.