Introduction: Nanotechnology is the science of using nano-sized materials and tools, and the word nano means
dwarf, which has Greek roots. Nano means one billionth (10-9
) and nanoparticles have a size of 1-
100 nm. Nanoparticles have various applications in chemistry, the food industry, pharmaceutical,
medicine, biotechnology, agriculture, cosmetics, textile, wastewater treatment, etc. Algae are the
simplest organisms with chlorophyll that lack roots, stems, leaves, reproductive organs, and
embryos. Algae are used to produce marine omega-3 fatty acids, including DHA and EPA, which
are very important for health. Algae are found in water, wet soil, trees and rocks and are the main
source of atmospheric oxygen production by taking in carbon dioxide and using plant
photosynthesis. Algae are rich in protein, polysaccharides, antioxidants, minerals, and vitamins.
Algae are also widely used in Agribusiness. Chlorella vulgaris is a single-cell green algae with a
spherical shape and a size of 5 to 10 microns, and it is one of the oldest algae on the planet, which
is used as a laboratory model due to its high resistance. Ag/ZnO nanoparticles have catalytic
photocatalytic and antimicrobial properties.
Methods: Synthesis of Ag/ZnO and treatment Ag/ZnO
The nanoparticles used in the present study were synthesized by Dr. Baharak Divband in the
Faculty of Chemistry of Tabriz University. A solution of 50 mg/L was prepared from zinc oxide
nanoparticles doped with silver, and to prevent nanoparticles from agglomeration, they were
dispersed in an ultrasonic bath. 1, 2.5, 5, and 7.5 Ag/ZnO nanoparticles were removed from the
prepared solution and added to 4 groups of algae with 100 ml size. The control group was also
prepared from algae.
Results: After treating the studied algae with 1, 2.5, 5, and 7.5 Ag/ZnO and measuring the activity of the
SOD enzyme after 24 hours of treatment, a significant increase in the activity of this enzyme (p
<0.05) showed in the mentioned concentrations. This increase in activity was not significant
between 2.5 and 5 concentrations and was significant at 7.5 concentrations. Catalase is an
antioxidant enzyme found in the chloroplast, mitochondria, peroxisome, and cytosol of plant cells
and can convert H2O2 into H2O and O2. In the present study, the amount of catalase enzyme
increased with increasing concentration of Ag/ZnO nanoparticles. The images prepared by
scanning electron microscope showed significant morphological changes in the surface of
Chlorella vulgaris algae in the treatment with Ag/ZnO nanoparticles. Morphological changes were
visible on the surface of Chlorella vulgaris cells. The toxicity of Ag/ZnO on C. vulgaris suggests
changes in morphology and dimensions.
Conclusion: Our studies on the effect of Ag/ZnO nanoparticles on Chlorella vulgarisshowed the morphological
changes of algae in the presence of these nanoparticles and damage to the wall and plasma
membrane. increase the antioxidant activity of SOD and CAT enzymes and decrease the amount
of H2O2 due to the activity of these enzymes it shows. Chlorophyll a, b, and total chlorophyll and
carotenoids showed a significant decrease in the presence of Ag/ZnO nanoparticles, which
indicated the toxicity of these nanoparticles on Chlorella vulgaris.
Keywords: Nanotechnology_ ROS_ Nanomaterials_ Cytotoxicity_ Antioxidant Enzymes_ Chlorella vulgaris_ SEM