A Zn-Al-Zr layered double hydroxide/graphene oxide nanocomposite enables rapid photocatalytic removal of kanamycin-resistance bacteria and genes via nano-confinement effects

Abstract

For efficient removal of the antibiotic-resistance bacteria and antibiotic-resistance genes, zirconium-doped zinc-aluminum layered double hydroxide/graphene oxide (Zn-Al-Zr LDHs/GO) nanocomposite has been developed. The Zn-Al-Zr LDHs/GO shows outstanding photocatalytic sterilization, inactivating kanamycin-resistance E. coli (6.53 log10 CFU/mL) under the full-wavelength light irradiation within 50 minutes. Owing to the 1O2 formation, it greatly disrupts the respiratory chain of the kanamycin-resistance E. coli, thereby leading to a declined yield of adenosine triphosphate, down-regulated expressions of the DNA ligase and polymerase proteins, as well as completely inhibited expressions of the DNA repair proteins. Meanwhile, the strong adsorption capability of the Zn-Al-Zr LDHs/GO towards phosphorus endows it with special nano-confinement effects for ARGs. It results in significantly enriched local concentration of the kanamycin-resistance genes on the Zn-Al-Zr LDHs/GO, consequently enhanced removal ability towards the kanamycin-resistance genes (4.70 log10 copies/mL in 3 hours). This work provides a new strategy for effectively removing the ARB and ARGs.