Exploration of Cytotoxicity and Antibacterial Activities of M-Ceo2 (M = Ag, Cu, Te, and Ta) Nanoparticles

Abstract

This study focuses on the ultrasonic synthesis of M-CeO₂ (M = Ag, Cu, Te & Ta) nanoparticles (NPs) and screening of their cytotoxicity and antibacterial activities. The prepared NPs are characterized by different techniques such as X-ray diffraction, transmission electron microscope, SEM-EDX,DR-UV-visible spectrophotometer, and dynamic light scattering analysis. The cytotoxicity of M-CeO₂ nanoparticles are assessed against cancer cells such as colorectal carcinoma (HCT-116) and cervical cancer cells (HeLa) and non-cancer cells (embryonic kidney cells HEK-293). The effect of post-48 h treatment of CeO₂, Ag-CeO_2, Cu-CeO₂, Te-CeO₂, and Ta-CeO₂, on HCT-116 and HeLa cells showed a noteworthy reduction in cell viability. The treatments of Ag-CeO₂ also display a reduction in cancer cell viability but statistically not significant. The treatment of CeO₂ shows better inhibitory action on HCT-116 and HeLa cells. HEK-293 is treated with CeO_2, Ag-CeO_2, Cu-CeO₂, Te-CeO_2, and Ta-CeO₂ NPs with the same dosages, there is a minor decline in the cell number, but the percentage of cells viability is greater than HCT-116 and HeLa cells. The antibacterial activity of NPs against E. coli and S. aureus is tested, and Te-CeO₂ NPs show better antibacterial activity. The lowest MIC displayed by Te-CeO₂ is 0.25 mg mL^-1 against E. coli and 4 mg mL^-1 for S. aureus, respectively.

Keywords: antibacterial; ceO2; cytotoxicity; nanoparticles.

Figure 1

XRD patterns of a) Ag‐CeO₂ NPs, b) Cu‐CeO₂ NPs, c) Te‐CeO₂ NPs, and d) Ta‐CeO₂ NPs.

Figure 2

TEM images of a) individual CeO₂ NPs, b) Ag‐CeO₂ NPs, c) Cu‐CeO₂ NPs, d) Te‐CeO₂ NPs, and e) Ta‐CeO₂ NPs. All scale bars are 100 nm.

Figure 3

Size histogram along with average size (in nm) of a) individual CeO₂ NPs, b) Ag‐CeO₂ NPs, c) Cu‐CeO₂ NPs, d) Te‐CeO₂ NPs, and e) Ta‐CeO₂ NPs.

Figure 4

EDX spectra and elemental composition (in weight and atomic percentage) of a) individual ceO₂ NPs, b) Ag‐CeO₂ NPs, c) Cu‐CeO₂ NPs, d) Te‐CeO₂ NPs, and e) Ta‐CeO₂ NPs.

Figure 5

SEM and corresponding EDX mapping images of a) individual CeO₂ NPs, b) Ag‐CeO₂ NPs, c) Cu‐CeO₂ NPs, d) Te‐CeO₂ NPs, and e) Ta‐CeO₂ NPs. All scale bars are 10 µm.

Figure 6

DR‐UV‐ spectra of CO₂, ag‐CeO₂, cu‐CeO₂, te‐CeO₂, and ta‐CeO₂ nanoparticles.

Figure 7

Effect of Ag‐CeO_2, Cu‐CeO₂, Te‐CeO_2, Ta‐CeO_2, and CeO₂ on cancer cells (HCT‐116, HeLa) and normal cells (HEK‐293) cells examined by MTT assay. *p < 0.005; **p < 0.001.

Figure 8

DAPI staining of HCT‐116 and Hela cells shows the influence of ceO₂ on cancer cells. a) (control group without treatment) shows healthy cells. b) CeO₂‐treated cells. c) The control cells of Hela shows healthy cells, d) shows that CeO₂‐treated cells showed apoptotic cell death. Magnifications 300x.

Figure 9

SEM micrographs displaying morphological changes in E. coli cells a) in the absence (control) and b) in the presence of Te‐CeO₂ NPs.

Figure 10

TEM images of the E. coli cell. a) The membrane of the control cells was intact and they were normal. b) The Te‐CeO₂ NPs‐treated cells were aberrant and lost their integrity due to damage to the cell membrane, which indicates NPs internalization.