Polyphenol stabilized copper nanoparticle formulations for rapid disinfection of bacteria and virus on diverse surfaces

Rapid and sustained disinfection of surfaces is necessary to check the spread of pathogenic microbes. The current study proposes a method of synthesis and use of copper nanoparticles (CuNPs) for contact disinfection of pathogenic microorganisms. Polyphenol stabilized CuNPs were synthesized by successive reductive disassembly and reassembly of copper phenolic complexes. Morphological and compositional characterization by transmission electron microscope (TEM), selected area diffraction and electron energy loss spectroscopy revealed monodispersed spherical (f 5-8 nm) CuNPs with coexisting Cu, Cu(I) and Cu (II) phases. Various commercial grade porous and non-porous substrates, such as, glass, stainless steel, cloth, plastic and silk were coated with the nanoparticles. Complete disinfection of 10⁷copies of surrogate enveloped and non-enveloped viruses: bacteriophage MS2, SUSP2, phi6; and gram negative as well as gram positive bacteria: Escherichia coli and Staphylococcus aureus was achieved on most substrates within minutes. Structural cell damage was further analytically confirmed by TEM. The formulation was well retained on woven cloth surfaces even after repeated washing, thereby revealing its promising potential for use in biosafe clothing. In the face of the current pandemic, the nanomaterials developed are also of commercial utility as an eco-friendly, mass producible alternative to bleach and alcohol based public space sanitizers used today.