Cymbopogon Citratus Functionalized Green Synthesis of CuO-Nanoparticles: Novel Prospects as Antibacterial and Antibiofilm Agents

Abstract

Chemically synthesized copper oxide nanoparticles (CuONPs) involve the generation of toxic products, which narrowed its biological application. Hence, we have developed a one-pot, green method for CuONP production employing the leaf extract of <i>Cymbopogon citratus</i> (CLE). Gas chromatography-mass spectrometry (GC-MS) analysis confirmed the capping of CuONPs by CLE esters (CLE-CuONPs). Fourier-transform infrared (FTIR) showed phenolics, sugars, and proteins mediated nucleation and stability of CLE-CuONPs. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed CLE-CuONPs between 11.4 to 14.5 nm. <i>Staphylococcus aureus</i>-1 (MRSA-1), <i>Staphylococcus aureus-</i>2 (MSSA-2) exposed to CLE-CuONPs (1500 µg/mL) showed 51.4%, 32.41% survival, while <i>Escherichia coli-</i>336 (<i>E. coli-</i>336) exposed to 1000 µg/mL CLE-CuONPs showed 45.27% survival. Scanning electron microscopy (SEM) of CLE-CuONPs treated <i>E. coli</i>-336, MSSA-2 and MRSA-1 showed morphological deformations. The biofilm production by <i>E. coli</i>-336 and MRSA-1 also declined to 33.0 ± 3.2% and 49.0 ± 3.1% at 2000 µg/mL of CLE-CuONPs. Atomic absorption spectroscopy (AAS) showed 22.80 ± 2.6%, 19.2 ± 4.2%, and 16.2 ± 3.6% accumulation of Cu²⁺ in <i>E. coli</i>-336, MSSA-2, and MRSA-1. Overall, the data exhibited excellent antibacterial and antibiofilm efficacies of esters functionalized CLE-CuONPs, indicating its putative application as a novel nano-antibiotic against multi drug resistance (MDR) pathogenic clinical isolates.