Document Type : Original Article
Authors
1
Protein Research Center, Shahid Beheshti University, Tehran, Iran
2
Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
3
Department of Medical laboratory science, College of Science, Knowledge University, Kirkuk Road, Erbil, Iraq
Abstract
Nanoparticles have impact in biomedical science due to their physical, chemical, and biological characteristics. Amongst, Zinc oxide nanoparticles (ZnO NPs), have been extensively studied for their applications in drug delivery, biosensing, and neuroprotection. However, the neurotoxicity and disruption of enzyme-based reactions have been controversial. In the present work, chemically synthesized ZnO NPs were characterized using UV–Vis spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), and scanning electron microscopy (SEM). Bio-interaction of ZnO NPs with tyrosine hydroxylase (TH), a rate-limiting enzyme for dopamine biosynthesis, was estimated by circular dichroism (CD) spectroscopy, ELISA-based activity assays, and SDS-PAGE for protein corona analysis. Cytotoxicity in PC12 neuronal cells was studied using MTT and live/dead staining. Results indicated ZnO NPs altered TH secondary structure (56.4 %), notably inhibited enzyme activity (56.4 %), and induced dose-dependent toxicity (IC₅₀ value of 0.312 μg/mL). These findings suggest ZnO NPs have a bivalent role in neurobiology: as potential medications, but uncontrolled exposure will exacerbate neuronal damage and Parkinson's disease progression.
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