Peony-shaped zinc oxide nanoflower synthesized via hydrothermal route exhibits promising anticancer and anti-amyloid activity

Abstract

Background: Cancer is the deadliest disease, and neurological disorders are also marked as slow progressive diseases, ultimately leading to death. Stopping two mouths with one morsel was the strategy that we used in this study.

Methods: We have synthesized peony-shaped zinc oxide nanoflowers (ZnO-NFs) and characterized them using various photophysical tools like UV-vis spectroscopy, zeta potential analysis, dynamic light scattering (DLS), FTIR, and scanning electron microscopy (SEM), and utilized these nanoflowers to monitor their anticancer and anti-amyloid activity. In vitro biocompatibility was assessed using fibroblasts and undifferentiated rat phaeochromocytoma cells, and in vivo, biocompatibility was estimated using haemolysis assay and zebrafish embryo development.

Results: The results demonstrated high biocompatibility of the as-synthesized ZnO-NFs up to a dose of 200 µg/ml. In vitro anticancer activity was evaluated using adherent (A375) and non-adherent (Dalton's Lymphoma Ascites, DLA) cancer cell lines. The results indicated that the ZnO-NFs significantly killed the cancer cells in a dose-dependent way, showing an extraordinary effect on DLA cells. The anti-amyloid activity in vitro was explored using a spectrum of assays that were hallmarks in anti-amyloid studies like ThT fluorescence assay, DLS, turbidity assay, atomic force microscopy (AFM), and SEM analysis. Excellent anti-amyloid activity was observed in vitro at 50 µg/ml of ZnO-NFs.

Conclusion: We can conclude from the above results that the as-synthesized ZnO-NFs have a dual role as an anticancer as well as an anti-amyloid agent. In the future, animal models can be used to study the efficacy of the ZnO-NFs in cancer inhibition and amyloid degradation.

Keywords: Amyloidosis; Anticancer activity; Biocompatibility; Zebrafish embryos; Zinc oxide nanoflowers.

Fig. 1

The (a) UV-visible spectrum (b) hydrodynamic diameter (c) zeta potential (d) FTIR and (e) XRD spectrum, and (f) SEM images of the synthesized ZnO-NFs (g) The HR-TEM images of the synthesized ZnO-NFs at 60,000 X magnification and (h) 1000000 X magnification (d spacing indicated by arrows)

Fig. 2

(a) The morphological observations under an inverted microscope (b) Live dead assay captured under a fluorescence microscope (c) MTT assay and (d) Cell viability percentage calculated using live-dead assay, of V79 cells after treatment with different doses of ZnO-NFs for 24 h. *** represents p < 0.001 compared to untreated control

Fig. 3

(a) The inverted microscopic images of PC12 cells (b) Live dead assay fluorescent microscopic image (c) MTT assay for cell viability, (d) Cell viability by Live dead assay of PC12 cells after treatment with different doses of ZnO-NFs for 24 h

Fig. 4

(a) The morphological observations under an inverted microscope (b) Live dead assay captured under a fluorescence microscope (c) MTT assay and (d) Cell viability percentage calculated using the live-dead assay of A375 cells after treatment with different doses of ZnO-NFs for 24 h. *** represents p < 0.001 compared to untreated control

Fig. 5

(a) Morphological observation using an inverted microscope for DLA cells (b) Light microscopic image of trypan blue stained cells loaded in a hemocytometer (c) MTT assay demonstrating cell DLA viability (d) Percentage of DLA cell viability using trypan blue dye exclusion assay, after treatment with different concentrations of ZnO-NFs for 24 h. *** represents p < 0.001 compared to untreated control

Fig. 6

(a) Images of RBC lysis after treatment with different doses of ZnO-NFs. Negative control was 0.9% NaCl, and positive control was distilled water (b) The percentage of hemolysis plotted for different samples (c) Microscopic images, and (d) Cumulative hatchability of zebrafish embryos captured at different hpf

Fig. 7

(a) The DLS peak (b) ThT fluorescence spectra at different concentrations, and (c) Turbidity assay graph of IA and IA + ZnO-NFs. (d) SEM image of IA, and (e) SEM image of IA + ZnO-NFs. AFM images of (f) IA and (g) IA + ZnO-NFs

Fig. 8

The ROS generation percentage of untreated control A375 cells and A375 cells treated with ZnO-NFs (50 µg/ml and 100 µg/ml) and positive control H₂O₂ (40 µg/ml)