Biosynthesis of zinc oxide nanoparticles by Pichia kudriavzevii GY1 and their biomedical properties
In the field of nanotechnology, the use ofvarious biological materials instead oftoxic chemicals for the synthesis of nanoparticles, has merited substantial attention. The use of toxic compounds limits their applications especially in biomedical field. To overcome the problem of toxicity in synth...
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/92114/1/FBSB%202018%2022%20-%20IR.pdf |
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| Summary: | In the field of nanotechnology, the use ofvarious biological materials instead oftoxic
chemicals for the synthesis of nanoparticles, has merited substantial attention. The
use of toxic compounds limits their applications especially in biomedical field. To
overcome the problem of toxicity in synthesis, safe eco-friendly green procedures
have a major role for producing nanoparticles. Among the many possible bio
resources, biologically active products from fungi and yeast represent high potential
for this purpose. The present research aims to study the potential ability of a new
yeast strain, Pichia kudriavzevii, in the synthesis of zinc oxide nanoparticles (ZnONPs)
in order to evaluate their physical and biomedical properties.
Zinc oxide nanoparticles (ZnO-NPs) were synthesized by a green method using
simple precursor from the solution consisting of zinc acetate and the fungal cell-free
filtrate of Pichia kudriavzevii GYl.The effect of reaction time (12, 24 and 36 h) on
the structure of the resulting ZnO nanoparticles was investigated. The samples were
characterized using Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis),
x-ray diffraction (XRD), transmission electron microscope (TEM), field emission
scanning electron microscope (FESEM), Photoluminescence (PL) and biomedical
tests as free radical scavenging activity, cytotoxicity, antibacterial and anticancer
activities.
From the XRD and TEM results, the ZnO-NPs with a hexagonal wurtzite structure
and a particle crystal size of ~10-61 nm were formed at different reaction times. The
most favourable nanosized structure with the lowest defect concentration was
obtained at intermediate duration (24 h). The ZnO-NPs showed strong DPPH free radical scavenging and a dose dependent toxicity with non-toxic effects on Vero cells
for concentrations below 190 ug/ml., The antibacterial tests reveal a favourable
antibacterial effect for those ZnO-NPs prepared at intermediate duration.
The anticancer activity ofbiosynthesized ZnO-NPs on breast cancer cells (MCF-7)
was determined using MTT assay. Cell cycle analysis and the mode of cell death
were evaluated using a flow cytometry instrument. Quantitative real-time-PCR
(qRT-PCR) was employed to investigate the expression ofapoptosis in MCF-7 cells.
ZnO NPs were cytotoxic to the MCF-7 cells in a dose-dependent manner. The 50%
growth inhibition concentration (IC50) of ZnO NPs at 24 h was 121 ug/ml., Cell
cycle analysis revealed that ZnO NPs induced sub-Gj phase (apoptosis), with values
of 1.87% at 0 ug/ml, (control), 71.49% at 1C25, 98.91% at IC50, and 99.44% at
IC75· Annexin V/propidium iodide (PI) flow cytometry analysis confirmed that ZnO
NPs induce apoptosis in MCF-7 cells. The pro-apoptotic genes p53, p2I, Bax, and
JNK were upregulated, whereas anti-apoptotic genes Bcl-2, AKTl, and ERKII2 were
downregulated in a dose-dependent manner. The arrest and apoptosis ofMCF-7 cells
were induced by ZnO NPs through several signalling pathways. Generally, the study
has successfully contributed to the knowledge on the discovery of using fast-growing
microorganism as a novel green approach in producing nanoparticles as new
materials for the current innovation of bionanotechnology field particularly for
medical applications. |
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