The Cytotoxic Effectiveness of Thiourea-Reduced Graphene Oxide on Human Lung Cancer Cells and Fungi

Abstract

This study demonstrated the effective reduction of graphene oxide (GO) by employing thiourea as a reducing and stabilizing agent. Two fungi (Aspergillus flavus and Aspergillus fumigatus) were used for anti-fungal assay. Cell viability, cell cycle analysis, DNA fragmentation, and cell morphology were assessed to determine the toxicity of thiourea-reduced graphene oxide (T-rGO) on human lung cancer cells. The results revealed that GO and T-rGO were hazardous to cells in a dose-dependent trend. The viability of both A. fumigatus and A. flavus was affected by GO and T-rGO. The reactive oxygen species produced by T-rGO caused the death of A. flavus and A. fumigatus cells. This study highlighted the effectiveness of T-rGO as an antifungal agent. In addition, T-rGO was found to be more harmful to cancer cells than GO. Thus, T-rGO manifested great potential in biological and biomedical applications.

Keywords: Aspergillus flavus; DNA fragmentation; antifungal activity; cell viability; lung cancer cells; reduced graphene oxide.

Figure 1

X-ray diffraction patterns of (a) GO and (b) T-rGO.

Figure 2

FESEM images of (a) GO and (b) T-rGO.

Figure 3

FTIR spectral analysis of (black line) GO and (red line) T-rGO.

Figure 4

Thermogravimetric analysis of (a) GO and (b) T-rGO.

Figure 5

Raman spectra of (a) GO and (b) T-rGO.

Figure 6

Antifungal activity of T-rGO nanosheets: mycelial growth of Aspergillus flavus on the PDA media containing different concentrations of reduced graphene oxide (25–500 µg/mL).

Figure 7

Antifungal activity of T-rGO nanosheets: mycelial growth of Aspergillus fumigatus on the PDA media containing different concentrations of reduced graphene oxide (25–500 µg/mL).

Figure 8

Plots of T-rGO concentration (µg/mL) vs. the activity that inhibits mycelial growth (percent).

Figure 9

Effects of GO and T-rGO on cell viability of human lung cancer cells. The viability of human lung cancer cells (A549) was determined after 24 h exposure to different concentrations of GO and T-rGO using the WST-8 assay, (Mean ± SD).

Figure 10

(a–c) Flowcytometric detection of apoptosis in phase of human lung cancer cells ((a): control; (b): GO-treated cells; (c): T-rGO-treated cells).

Figure 11

DNA fragmentation. Cells were incubated with GO (62.5 µg/mL) and T-rGO (62.5 µg/mL) for 24 h; after incubation, DNA was extracted from cells and resolved on agarose gel electrophoresis.

Figure 12

(a) Anticancer effect of GO on A549 human lung cancer cells; (b) anticancer effect of T-rGO on A549 human lung cancer cells.